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Butterworth PJ, Bajka BH, Edwards CH, Warren FJ, Ellis PR. Enzyme kinetic approach for mechanistic insight and predictions of in vivo starch digestibility and the glycaemic index of foods. Trends Food Sci Technol 2022; 120:254-264. [PMID: 35210697 PMCID: PMC8850932 DOI: 10.1016/j.tifs.2021.11.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 11/09/2021] [Accepted: 11/14/2021] [Indexed: 12/18/2022]
Abstract
Background Starch is a principal dietary source of digestible carbohydrate and energy. Glycaemic and insulinaemic responses to foods containing starch vary considerably and glucose responses to starchy foods are often described by the glycaemic index (GI) and/or glycaemic load (GL). Low GI/GL foods are beneficial in the management of cardiometabolic disorders (e.g., type 2 diabetes, cardiovascular disease). Differences in rates and extents of digestion of starch-containing foods will affect postprandial glycaemia. Scope and approach Amylolysis kinetics are influenced by structural properties of the food matrix and of starch itself. Native (raw) semi-crystalline starch is digested slowly but hydrothermal processing (cooking) gelatinises the starch and greatly increases its digestibility. In plants, starch granules are contained within cells and intact cell walls can limit accessibility of water and digestive enzymes hindering gelatinisation and digestibility. In vitro studies of starch digestion by α-amylase model early stages in digestion and can suggest likely rates of digestion in vivo and expected glycaemic responses. Reports that metabolic responses to dietary starch are influenced by α-amylase gene copy number, heightens interest in amylolysis. Key findings and conclusions This review shows how enzyme kinetic strategies can provide explanations for differences in digestion rate of different starchy foods. Michaelis-Menten and Log of Slope analyses provide kinetic parameters (e.g., Km and kcat/Km) for evaluating catalytic efficiency and ease of digestibility of starch by α-amylase. Suitable kinetic methods maximise the information that can be obtained from in vitro work for predictions of starch digestion and glycaemic responses in vivo. Michaelis-Menten kinetics determines catalytic efficiency of amylase action on starch. Kinetic parameters Km and kcat/Km are useful for estimating ease of digestibility. Log of slope analysis can quantify starch fractions digested at different rates. Categorisation of Resistant Starch can be based on types of interaction with amylase. Enzyme kinetic studies of amylolysis are useful for predicting postprandial glycaemia.
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Affiliation(s)
- Peter J. Butterworth
- Biopolymers Group, Departments of Biochemistry and Nutritional Sciences, Faculty of Life Sciences and Medicine, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
| | - Balázs H. Bajka
- Biopolymers Group, Departments of Biochemistry and Nutritional Sciences, Faculty of Life Sciences and Medicine, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
| | - Cathrina H. Edwards
- Quadram Institute Bioscience, Rosalind Franklin Road, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - Frederick J. Warren
- Quadram Institute Bioscience, Rosalind Franklin Road, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - Peter R. Ellis
- Biopolymers Group, Departments of Biochemistry and Nutritional Sciences, Faculty of Life Sciences and Medicine, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
- Corresponding author. Biopolymers Group, Departments of Biochemistry and Nutritional Sciences, King's College London, 150 Stamford Street, London, SE1 9NH, UK.
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Edwards CH, Veerabahu AS, Mason AJ, Butterworth PJ, Ellis PR. α-Amylase action on starch in chickpea flour following hydrothermal processing and different drying, cooling and storage conditions. Carbohydr Polym 2021; 259:117738. [PMID: 33674022 PMCID: PMC7965859 DOI: 10.1016/j.carbpol.2021.117738] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 01/10/2021] [Accepted: 01/25/2021] [Indexed: 02/06/2023]
Abstract
Starch is present in many prepared 'ready-meals' that have undergone processing and/or storage in frozen or chilled state. Hydrothermal processing greatly increases starch digestibility and postprandial glycaemia. Effects of different heating/drying and cooling regimes on amylolysis have received little attention. Hence, we examined the effects of different processing treatments on in vitro digestibility of starch in chickpea flour. Solid-state 13C NMR was used to estimate ordered double-helical structure in the starch. Native starch with 25 % double-helical content was the most resistant to digestion but hydrothermal processing (gelatinisation) resulted in >95 % loss of order and a large increase in starch digestibility. Air-drying of pre-treated flour produced slowly-digestible starch (C∞, 55.9 %). Refrigeration of gelatinised samples decreased ease of amylolysis coincident with increase in double-helical content. Freezing maintained the same degree of digestibility as freshly gelatinised material and produced negligible retrogradation. Chilling may be exploited to produce ready-meals with a lower glycaemic response.
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Affiliation(s)
- Cathrina H Edwards
- King's College London, Faculty of Life Sciences and Medicine, Departments of Biochemistry and Nutritional Sciences, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom.
| | - Amalia S Veerabahu
- King's College London, Faculty of Life Sciences and Medicine, Departments of Biochemistry and Nutritional Sciences, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom.
| | - A James Mason
- King's College London, School of Cancer & Pharmaceutical Science, Institute of Pharmaceutical Science, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom.
| | - Peter J Butterworth
- King's College London, Faculty of Life Sciences and Medicine, Departments of Biochemistry and Nutritional Sciences, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom.
| | - Peter R Ellis
- King's College London, Faculty of Life Sciences and Medicine, Departments of Biochemistry and Nutritional Sciences, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom.
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Edwards CH, Ryden P, Mandalari G, Butterworth PJ, Ellis PR. Structure-function studies of chickpea and durum wheat uncover mechanisms by which cell wall properties influence starch bioaccessibility. Nat Food 2021; 2:118-126. [PMID: 34667952 PMCID: PMC7611843 DOI: 10.1038/s43016-021-00230-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 01/18/2021] [Indexed: 01/18/2023]
Abstract
Positive health effects of dietary fibre have been established; however, the underpinning mechanisms are not well understood. Plant cell walls are the predominant source of fibre in the diet. They encapsulate intracellular starch and delay digestive enzyme ingress, but food processing can disrupt the structure. Here we compare digestion kinetics of chickpea (cotyledon) and durum wheat (endosperm), which have contrasting cell wall structures (Type I and II, respectively), to investigate a 'cell-wall barrier' mechanism that may underpin the health effects of dietary fibre. Using in vitro models, including the Dynamic Gastric Model, to simulate human digestion together with microscopy, we show that starch bioaccessibility is limited from intact plant cells and that processing treatments can have different effects on cell integrity and digestion kinetics when applied to tissues with contrasting cell wall properties. This new understanding of dietary fibre structure is important for effective fibre supplementation to benefit human health.
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Affiliation(s)
- Cathrina H. Edwards
- Biopolymers Group, Departments of Biochemistry and Nutritional Sciences, Faculty of Life Sciences and Medicine, King’s College London, SE1 9NH, London, UK
- Quadram Institute Bioscience, Norwich Research Park, NR4 7UQ, Norwich, UK
| | - Peter Ryden
- Quadram Institute Bioscience, Norwich Research Park, NR4 7UQ, Norwich, UK
| | - Giuseppina Mandalari
- Quadram Institute Bioscience, Norwich Research Park, NR4 7UQ, Norwich, UK
- Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, Vill. SS. Annunziata, 98168, Messina, Italy
| | - Peter J. Butterworth
- Biopolymers Group, Departments of Biochemistry and Nutritional Sciences, Faculty of Life Sciences and Medicine, King’s College London, SE1 9NH, London, UK
| | - Peter R. Ellis
- Biopolymers Group, Departments of Biochemistry and Nutritional Sciences, Faculty of Life Sciences and Medicine, King’s College London, SE1 9NH, London, UK
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Prpa EJ, Bajka BH, Ellis PR, Butterworth PJ, Corpe CP, Hall WL. A systematic review of in vitro studies evaluating the inhibitory effects of polyphenol-rich fruit extracts on carbohydrate digestive enzymes activity: a focus on culinary fruits consumed in Europe. Crit Rev Food Sci Nutr 2020; 61:3783-3803. [PMID: 32838552 DOI: 10.1080/10408398.2020.1808585] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Evidence shows that polyphenols can attenuate postprandial blood glucose responses to meals containing digestible carbohydrate. Polyphenol-rich plant extracts are emerging as potential ingredients in functional foods and/or beverages despite limited understanding of their physiological effects. Many studies have investigated the mechanisms of polyphenol-rich fruit extracts on inhibition of digestive enzymes. However, the evidence available has yet to be critically evaluated systematically. This report reviews the in vitro literature to quantify the effect of fruit polyphenol extracts on the activities of digestive carbohydrases. A systematic literature search was conducted using six science databases. Included studies, totaling 34 in number, were in vitro digestion models which quantified gut digestive enzyme(s) activity on starch digestion in the presence of fruit polyphenol extracts. Most studies assessed the effects of fruit extracts on either α-amylase (n = 30) or α-glucosidase (n = 30) activity. Studies were consistent overall in showing stronger inhibition of α-amylase compared to α-glucosidase by proanthocyanidin- and/or ellagitannin-rich fruit extracts. Recommendations are proposed for future reporting of this type of research to enable meaningful synthesis of the literature as a whole. Such knowledge could allow effective choices to be made for development of novel functional foods and beverages.
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Affiliation(s)
- E J Prpa
- Faculty of Life Sciences and Medicine, Department of Nutritional Sciences, King's College London, London, UK
| | - B H Bajka
- Faculty of Life Sciences and Medicine, Department of Biochemistry and Nutritional Sciences, Biopolymers Group, King's College London, London, UK
| | - P R Ellis
- Faculty of Life Sciences and Medicine, Department of Biochemistry and Nutritional Sciences, Biopolymers Group, King's College London, London, UK
| | - P J Butterworth
- Faculty of Life Sciences and Medicine, Department of Biochemistry and Nutritional Sciences, Biopolymers Group, King's College London, London, UK
| | - C P Corpe
- Faculty of Life Sciences and Medicine, Department of Nutritional Sciences, King's College London, London, UK
| | - W L Hall
- Faculty of Life Sciences and Medicine, Department of Nutritional Sciences, King's College London, London, UK
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Ni D, Ai Z, Munoz-Sandoval D, Suresh R, Ellis PR, Yuqiong C, Sharp PA, Butterworth PJ, Yu Z, Corpe CP. Inhibition of the facilitative sugar transporters (GLUTs) by tea extracts and catechins. FASEB J 2020; 34:9995-10010. [PMID: 32564472 DOI: 10.1096/fj.202000057rr] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 04/17/2020] [Accepted: 05/05/2020] [Indexed: 01/21/2023]
Abstract
Tea polyphenolics have been suggested to possess blood glucose lowering properties by inhibiting sugar transporters in the small intestine and improving insulin sensitivity. In this report, we studied the effects of teas and tea catechins on the small intestinal sugar transporters, SGLT1 and GLUTs (GLUT1, 2 and 5). Green tea extract (GT), oolong tea extract (OT), and black tea extract (BT) inhibited glucose uptake into the intestinal Caco-2 cells with GT being the most potent inhibitor (IC50 : 0.077 mg/mL), followed by OT (IC50 : 0.136 mg/mL) and BT (IC50 : 0.56 mg/mL). GT and OT inhibition of glucose uptake was partial non-competitive, with an inhibitor constant (Ki ) = 0.0317 and 0.0571 mg/mL, respectively, whereas BT was pure non-competitive, Ki = 0.36 mg/mL. Oocytes injected to express small intestinal GLUTs were inhibited by teas, but SGLT1 was not. Furthermore, catechins present in teas were the predominant inhibitor of glucose uptake into Caco-2 cells, and gallated catechins the most potent: CG > ECG > EGCG ≥ GCG when compared to the non-gallated catechins (C, EC, GC, and EGC). In Caco-2 cells, individual tea catechins reduced the SGLT1 gene, but not protein expression levels. In contrast, GLUT2 gene and protein expression levels were reduced after 2 hours exposure to catechins but increased after 24 hours. These in vitro studies suggest teas containing catechins may be useful dietary supplements capable of blunting postprandial glycaemia in humans, including those with or at risk to Type 2 diabetes mellitus.
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Affiliation(s)
- Dejiang Ni
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan City, China.,Faculty of Life Sciences and Medicine, Departments of Biochemistry and Nutrition, King's College London, London, UK
| | - Zeyi Ai
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan City, China.,Institute of Leisure Agriculture, Jiangsu Academy of Agricultural Sciences, Nanjing City, China
| | - Diana Munoz-Sandoval
- Faculty of Life Sciences and Medicine, Department of Nutritional Sciences, King's College London, London, UK
| | - Reshma Suresh
- Faculty of Life Sciences and Medicine, Department of Nutritional Sciences, King's College London, London, UK
| | - Peter R Ellis
- Faculty of Life Sciences and Medicine, Departments of Biochemistry and Nutrition, King's College London, London, UK
| | - Chen Yuqiong
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan City, China
| | - Paul A Sharp
- Faculty of Life Sciences and Medicine, Department of Nutritional Sciences, King's College London, London, UK
| | - Peter J Butterworth
- Faculty of Life Sciences and Medicine, Departments of Biochemistry and Nutrition, King's College London, London, UK
| | - Zhi Yu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan City, China
| | - Christopher P Corpe
- Faculty of Life Sciences and Medicine, Department of Nutritional Sciences, King's College London, London, UK
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Edwards CH, Ryden P, Pinto AM, van der Schoot A, Stocchi C, Perez-Moral N, Butterworth PJ, Bajka B, Berry SE, Hill SE, Ellis PR. Chemical, physical and glycaemic characterisation of PulseON®: A novel legume cell-powder ingredient for use in the design of functional foods. J Funct Foods 2020. [DOI: 10.1016/j.jff.2020.103918] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Delamare GY, Butterworth PJ, Ellis PR, Hill S, Warren FJ, Edwards CH. Incorporation of a novel leguminous ingredient into savoury biscuits reduces their starch digestibility: Implications for lowering the Glycaemic Index of cereal products. Food Chem X 2020; 5:100078. [PMID: 32140680 PMCID: PMC7047182 DOI: 10.1016/j.fochx.2020.100078] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 01/14/2020] [Accepted: 01/20/2020] [Indexed: 01/05/2023] Open
Abstract
Many carbohydrate foods contain starch that is rapidly digested and elicits a high Glycaemic Index. A legume ingredient (PulseON®) rich in Type 1 resistant starch (RS1) was recently developed; however, its potential as a functional ingredient when processed into a food product required assessment. PulseON® was used to replace 0, 25, 50, 75, and 100% of the wheat flour in a savoury biscuit recipe. In vitro starch digestion kinetics of biscuits and water-holding properties of ingredients were assessed. The RS1 in PulseON® did not appear to be structurally compromised during biscuit making. Replacing 50% wheat flour with PulseON® reduced the starch hydrolysis index of biscuits by nearly 60%. This seems to result from the ingredients' impact on water availability for starch gelatinisation. Overall, these findings highlight the potential of using biscuits as a food vehicle for PulseON® to increase consumer intakes of legume protein, dietary fibre, and potentially low glycaemic starch.
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Affiliation(s)
- Gael Y.F. Delamare
- Quadram Institute Bioscience, Norwich Research Park, Colney, Norwich NR4 7UQ, United Kingdom
| | - Peter J. Butterworth
- Biopolymers Group, Departments of Biochemistry and Nutritional Sciences, Faculty of Life Sciences and Medicine, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom
| | - Peter R. Ellis
- Biopolymers Group, Departments of Biochemistry and Nutritional Sciences, Faculty of Life Sciences and Medicine, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom
| | - Sandra Hill
- Biopolymer Solutions Ltd., College Road, Sutton Bonington, Loughborough LE12 5RD, United Kingdom
| | - Frederick J. Warren
- Quadram Institute Bioscience, Norwich Research Park, Colney, Norwich NR4 7UQ, United Kingdom
| | - Cathrina H. Edwards
- Quadram Institute Bioscience, Norwich Research Park, Colney, Norwich NR4 7UQ, United Kingdom
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Channell GA, Adams GG, Lu Y, Gillis RB, Dinu V, Grundy MML, Bajka B, Butterworth PJ, Ellis PR, Mackie A, Ballance S, Harding SE. Use of the Extended Fujita method for representing the molecular weight and molecular weight distributions of native and processed oat beta-glucans. Sci Rep 2018; 8:11809. [PMID: 30087367 PMCID: PMC6081461 DOI: 10.1038/s41598-018-29997-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 07/18/2018] [Indexed: 11/08/2022] Open
Abstract
Beta 1-3, 1-4 glucans ("beta-glucans") are one of the key components of the cell wall of cereals, complementing the main structural component cellulose. Beta-glucans are also an important source of soluble fibre in foods containing oats with claims of other beneficial nutritional properties such as plasma cholesterol lowering in humans. Key to the function of beta-glucans is their molecular weight and because of their high polydispersity - molecular weight distribution. Analytical ultracentrifugation provides a matrix-free approach (not requiring separation columns or media) to polymer molecular weight distribution determination. The sedimentation coefficient distribution is converted to a molecular weight distribution via a power law relation using an established procedure known as the Extended Fujita approach. We establish and apply the power law relation and Extended Fujita method for the first time to a series of native and processed oat beta-glucans. The application of this approach to beta-glucans from other sources is considered.
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Affiliation(s)
- Guy A Channell
- National Centre for Macromolecular Hydrodynamics, The University of Nottingham, Sutton Bonington, LE12 5RD, UK
| | - Gary G Adams
- National Centre for Macromolecular Hydrodynamics, The University of Nottingham, Sutton Bonington, LE12 5RD, UK
- Faculty of Medicine and Health Sciences, Queens Medical Centre, University of Nottingham, Nottingham, NG7 2HA, UK
| | - YuDong Lu
- National Centre for Macromolecular Hydrodynamics, The University of Nottingham, Sutton Bonington, LE12 5RD, UK
| | - Richard B Gillis
- National Centre for Macromolecular Hydrodynamics, The University of Nottingham, Sutton Bonington, LE12 5RD, UK
- Faculty of Medicine and Health Sciences, Queens Medical Centre, University of Nottingham, Nottingham, NG7 2HA, UK
| | - Vlad Dinu
- National Centre for Macromolecular Hydrodynamics, The University of Nottingham, Sutton Bonington, LE12 5RD, UK
| | - Myriam M-L Grundy
- School of Agriculture, The Sustainable Agricultural and Food Systems Research Division, Reading, RG6 6AR, UK
| | - Balazs Bajka
- Biopolymers Group, Department Nutritional Sciences, Kings College London, London, SE1 9NH, UK
| | - Peter J Butterworth
- Biopolymers Group, Department Nutritional Sciences, Kings College London, London, SE1 9NH, UK
| | - Peter R Ellis
- Biopolymers Group, Department Nutritional Sciences, Kings College London, London, SE1 9NH, UK
| | - Alan Mackie
- School of Food Science & Nutrition, University of Leeds, Leeds, LS2 9JT, UK
| | - Simon Ballance
- Nofima AS, Norwegian Institute of Food, Fisheries and Aquaculture Research, Ås, Norway
| | - Stephen E Harding
- National Centre for Macromolecular Hydrodynamics, The University of Nottingham, Sutton Bonington, LE12 5RD, UK.
- Kulturhistorisk Museum, Universitetet i Oslo, Postboks 6762, St. Olavs plass, 0130, Oslo, Norway.
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Patel H, Royall PG, Gaisford S, Williams GR, Edwards CH, Warren FJ, Flanagan BM, Ellis PR, Butterworth PJ. Structural and enzyme kinetic studies of retrograded starch: Inhibition of α-amylase and consequences for intestinal digestion of starch. Carbohydr Polym 2017; 164:154-161. [PMID: 28325312 PMCID: PMC5374268 DOI: 10.1016/j.carbpol.2017.01.040] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 01/09/2017] [Accepted: 01/10/2017] [Indexed: 11/20/2022]
Abstract
Retrograded starch is known to be resistant to digestion. We used enzyme kinetic experiments to examine how retrogradation of starch affects amylolysis catalysed by porcine pancreatic amylase. Parallel studies employing differential scanning calorimetry, infra red spectroscopy, X-ray diffraction and NMR spectroscopy were performed to monitor changes in supramolecular structure of gelatinised starch as it becomes retrograded. The total digestible starch and the catalytic efficiency of amylase were both decreased with increasing evidence of retrogradation. A purified sample of retrograded high amylose starch inhibited amylase directly. These new findings demonstrate that amylase binds to retrograded starch. Therefore consumption of retrograded starch may not only be beneficial to health through depletion of total digestible starch, and therefore the metabolisable energy, but may also slow the rate of intestinal digestion through direct inhibition of α-amylase. Such physiological effects have important implications for the prevention and management of type 2 diabetes and cardiovascular disease.
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Affiliation(s)
- Hamung Patel
- King's College London, Faculty of Life Sciences and Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom
| | - Paul G Royall
- King's College London, Faculty of Life Sciences and Medicine, Institute of Pharmaceutical Science, Drug Delivery Group, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom
| | - Simon Gaisford
- UCL School of Pharmacy, University College, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom
| | - Gareth R Williams
- UCL School of Pharmacy, University College, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom
| | - Cathrina H Edwards
- King's College London, Faculty of Life Sciences and Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom; Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, United Kingdom
| | - Frederick J Warren
- Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, United Kingdom; Excellence in Plant Cell Walls, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Bernadine M Flanagan
- Excellence in Plant Cell Walls, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Peter R Ellis
- King's College London, Faculty of Life Sciences and Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom
| | - Peter J Butterworth
- King's College London, Faculty of Life Sciences and Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom.
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Dhital S, Warren FJ, Butterworth PJ, Ellis PR, Gidley MJ. Mechanisms of starch digestion by α-amylase-Structural basis for kinetic properties. Crit Rev Food Sci Nutr 2017; 57:875-892. [PMID: 25751598 DOI: 10.1080/10408398.2014.922043] [Citation(s) in RCA: 257] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Recent studies of the mechanisms determining the rate and extent of starch digestion by α-amylase are reviewed in the light of current widely-used classifications for (a) the proportions of rapidly-digestible (RDS), slowly-digestible (SDS), and resistant starch (RS) based on in vitro digestibility, and (b) the types of resistant starch (RS 1,2,3,4…) based on physical and/or chemical form. Based on methodological advances and new mechanistic insights, it is proposed that both classification systems should be modified. Kinetic analysis of digestion profiles provides a robust set of parameters that should replace the classification of starch as a combination of RDS, SDS, and RS from a single enzyme digestion experiment. This should involve determination of the minimum number of kinetic processes needed to describe the full digestion profile, together with the proportion of starch involved in each process, and the kinetic properties of each process. The current classification of resistant starch types as RS1,2,3,4 should be replaced by one which recognizes the essential kinetic nature of RS (enzyme digestion rate vs. small intestinal passage rate), and that there are two fundamental origins for resistance based on (i) rate-determining access/binding of enzyme to substrate and (ii) rate-determining conversion of substrate to product once bound.
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Affiliation(s)
- Sushil Dhital
- a ARC Centre of Excellence in Plant Cell Walls , Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland , St Lucia , Australia
| | - Frederick J Warren
- b Centre for Nutrition and Food Sciences , Queensland Alliance for Agriculture and Food Innovation, The University of Queensland , St Lucia , Australia
| | - Peter J Butterworth
- c King's College London , Diabetes and Nutritional Sciences Division, Biopolymers Group , London , UK
| | - Peter R Ellis
- c King's College London , Diabetes and Nutritional Sciences Division, Biopolymers Group , London , UK
| | - Michael J Gidley
- a ARC Centre of Excellence in Plant Cell Walls , Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland , St Lucia , Australia
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Edwards CH, Rossi M, Corpe CP, Butterworth PJ, Ellis PR. The role of sugars and sweeteners in food, diet and health: Alternatives for the future. Trends Food Sci Technol 2016. [DOI: 10.1016/j.tifs.2016.07.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Grundy MML, Edwards CH, Mackie AR, Gidley MJ, Butterworth PJ, Ellis PR. Re-evaluation of the mechanisms of dietary fibre and implications for macronutrient bioaccessibility, digestion and postprandial metabolism. Br J Nutr 2016; 116:816-33. [PMID: 27385119 PMCID: PMC4983777 DOI: 10.1017/s0007114516002610] [Citation(s) in RCA: 188] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 06/01/2016] [Accepted: 06/08/2016] [Indexed: 02/06/2023]
Abstract
The positive effects of dietary fibre on health are now widely recognised; however, our understanding of the mechanisms involved in producing such benefits remains unclear. There are even uncertainties about how dietary fibre in plant foods should be defined and analysed. This review attempts to clarify the confusion regarding the mechanisms of action of dietary fibre and deals with current knowledge on the wide variety of dietary fibre materials, comprising mainly of NSP that are not digested by enzymes of the gastrointestinal (GI) tract. These non-digestible materials range from intact cell walls of plant tissues to individual polysaccharide solutions often used in mechanistic studies. We discuss how the structure and properties of fibre are affected during food processing and how this can impact on nutrient digestibility. Dietary fibre can have multiple effects on GI function, including GI transit time and increased digesta viscosity, thereby affecting flow and mixing behaviour. Moreover, cell wall encapsulation influences macronutrient digestibility through limited access to digestive enzymes and/or substrate and product release. Moreover, encapsulation of starch can limit the extent of gelatinisation during hydrothermal processing of plant foods. Emphasis is placed on the effects of diverse forms of fibre on rates and extents of starch and lipid digestion, and how it is important that a better understanding of such interactions with respect to the physiology and biochemistry of digestion is needed. In conclusion, we point to areas of further investigation that are expected to contribute to realisation of the full potential of dietary fibre on health and well-being of humans.
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Affiliation(s)
- Myriam M.-L. Grundy
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
| | - Cathrina H. Edwards
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
- Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK
| | - Alan R. Mackie
- Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK
| | - Michael J. Gidley
- ARC Centre of Excellence in Plant Cell Walls, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane 4072, Qsd, Australia
| | - Peter J. Butterworth
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
| | - Peter R. Ellis
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
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13
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Grundy MML, Carrière F, Mackie AR, Gray DA, Butterworth PJ, Ellis PR. The role of plant cell wall encapsulation and porosity in regulating lipolysis during the digestion of almond seeds. Food Funct 2016; 7:69-78. [DOI: 10.1039/c5fo00758e] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Intact cell walls of almond prevent lipase penetration thus hindering lipid digestion.
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Affiliation(s)
- Myriam M. L. Grundy
- King's College London
- Diabetes and Nutritional Sciences Division
- London SE1 9NH
- UK
| | - Frédéric Carrière
- CNRS
- Aix-Marseille Université
- UMR 7282
- Enzymologie Interfaciale et Physiologie de la Lipolyse
- 13402 Marseille Cedex 20
| | | | - David A. Gray
- University of Nottingham
- Division of Food Sciences
- School of Biosciences
- Leicestershire
- UK
| | | | - Peter R. Ellis
- King's College London
- Diabetes and Nutritional Sciences Division
- London SE1 9NH
- UK
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14
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Warren FJ, Perston BB, Galindez-Najera SP, Edwards CH, Powell PO, Mandalari G, Campbell GM, Butterworth PJ, Ellis PR. Infrared microspectroscopic imaging of plant tissues: spectral visualization of Triticum aestivum kernel and Arabidopsis leaf microstructure. Plant J 2015; 84:634-46. [PMID: 26400058 PMCID: PMC4620737 DOI: 10.1111/tpj.13031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 08/28/2015] [Accepted: 09/08/2015] [Indexed: 05/24/2023]
Abstract
Infrared microspectroscopy is a tool with potential for studies of the microstructure, chemical composition and functionality of plants at a subcellular level. Here we present the use of high-resolution bench top-based infrared microspectroscopy to investigate the microstructure of Triticum aestivum L. (wheat) kernels and Arabidopsis leaves. Images of isolated wheat kernel tissues and whole wheat kernels following hydrothermal processing and simulated gastric and duodenal digestion were generated, as well as images of Arabidopsis leaves at different points during a diurnal cycle. Individual cells and cell walls were resolved, and large structures within cells, such as starch granules and protein bodies, were clearly identified. Contrast was provided by converting the hyperspectral image cubes into false-colour images using either principal component analysis (PCA) overlays or by correlation analysis. The unsupervised PCA approach provided a clear view of the sample microstructure, whereas the correlation analysis was used to confirm the identity of different anatomical structures using the spectra from isolated components. It was then demonstrated that gelatinized and native starch within cells could be distinguished, and that the loss of starch during wheat digestion could be observed, as well as the accumulation of starch in leaves during a diurnal period.
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Affiliation(s)
- Frederick J Warren
- King's College London, Faculty of Life Sciences and Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, LondonFranklin-Wilkins Building, 150, Stamford Street, London, SE1 9NH, United Kingdom
- ARC Centre of Excellence in Plant Cell Walls, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, The University of QueenslandSt. Lucia, Brisbane, Queensland, 4072, Australia
| | - Benjamin B Perston
- PerkinElmerChalfont Road, Seer Green, Buckinghamshire, HP9 2FX, United Kingdom
| | - Silvia P Galindez-Najera
- Satake Centre for Grain Process Engineering, School of Chemical Engineering and Analytical Science, The University of ManchesterM13 9PL, Manchester, United Kingdom
| | - Cathrina H Edwards
- King's College London, Faculty of Life Sciences and Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, LondonFranklin-Wilkins Building, 150, Stamford Street, London, SE1 9NH, United Kingdom
| | - Prudence O Powell
- ARC Centre of Excellence in Plant Cell Walls, Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, The University of QueenslandSt. Lucia, Brisbane, Queensland, 4072, Australia
| | - Giusy Mandalari
- The Model Gut, Institute of Food Research, Norwich Research ParkColney Lane, NR4 7UA, Norwich, United Kingdom
- Department of Drug Science and Products for Health, University of MessinaVill. SS. Annunziata, 98168, Messina, Italy
| | - Grant M Campbell
- Satake Centre for Grain Process Engineering, School of Chemical Engineering and Analytical Science, The University of ManchesterM13 9PL, Manchester, United Kingdom
| | - Peter J Butterworth
- King's College London, Faculty of Life Sciences and Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, LondonFranklin-Wilkins Building, 150, Stamford Street, London, SE1 9NH, United Kingdom
| | - Peter R Ellis
- King's College London, Faculty of Life Sciences and Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, LondonFranklin-Wilkins Building, 150, Stamford Street, London, SE1 9NH, United Kingdom
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15
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Edwards CH, Grundy MM, Grassby T, Vasilopoulou D, Frost GS, Butterworth PJ, Berry SE, Sanderson J, Ellis PR. Manipulation of starch bioaccessibility in wheat endosperm to regulate starch digestion, postprandial glycemia, insulinemia, and gut hormone responses: a randomized controlled trial in healthy ileostomy participants. Am J Clin Nutr 2015; 102:791-800. [PMID: 26333512 PMCID: PMC4588739 DOI: 10.3945/ajcn.114.106203] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 07/31/2015] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Cereal crops, particularly wheat, are a major dietary source of starch, and the bioaccessibility of starch has implications for postprandial glycemia. The structure and properties of plant foods have been identified as critical factors in influencing nutrient bioaccessibility; however, the physical and biochemical disassembly of cereal food during digestion has not been widely studied. OBJECTIVES The aims of this study were to compare the effects of 2 porridge meals prepared from wheat endosperm with different degrees of starch bioaccessibility on postprandial metabolism (e.g., glycemia) and to gain insight into the structural and biochemical breakdown of the test meals during gastroileal transit. DESIGN A randomized crossover trial in 9 healthy ileostomy participants was designed to compare the effects of 55 g starch, provided as coarse (2-mm particles) or smooth (<0.2-mm particles) wheat porridge, on postprandial changes in blood glucose, insulin, C-peptide, lipids, and gut hormones and on the resistant starch (RS) content of ileal effluent. Undigested food in the ileal output was examined microscopically to identify cell walls and encapsulated starch. RESULTS Blood glucose, insulin, C-peptide, and glucose-dependent insulinotropic polypeptide concentrations were significantly lower (i.e., 33%, 43%, 40%, and 50% lower 120-min incremental AUC, respectively) after consumption of the coarse porridge than after the smooth porridge (P < 0.01). In vitro, starch digestion was slower in the coarse porridge than in the smooth porridge (33% less starch digested at 90 min, P < 0.05, paired t test). In vivo, the structural integrity of coarse particles (∼2 mm) of wheat endosperm was retained during gastroileal transit. Microscopic examination revealed a progressive loss of starch from the periphery toward the particle core. The structure of the test meal had no effect on the amount or pattern of RS output. CONCLUSION The structural integrity of wheat endosperm is largely retained during gastroileal digestion and has a primary role in influencing the rate of starch amylolysis and, consequently, postprandial metabolism. This trial was registered at isrctn.org as ISRCTN40517475.
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Affiliation(s)
- Cathrina H Edwards
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom
| | - Myriam Ml Grundy
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom
| | - Terri Grassby
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom
| | - Dafni Vasilopoulou
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom
| | - Gary S Frost
- Nutrition and Dietetic Research Group, Faculty of Medicine, Hammersmith Campus, Imperial College, London, United Kingdom
| | - Peter J Butterworth
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom
| | - Sarah Ee Berry
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom
| | - Jeremy Sanderson
- Department of Gastroenterology, Guy's and St. Thomas' National Health Service Foundation Trust, London, United Kingdom; and
| | - Peter R Ellis
- Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom;
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16
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Baldwin AJ, Egan DL, Warren F, Barker PD, Dobson CM, Butterworth PJ, Ellis PR. Investigating the mechanisms of amylolysis of starch granules by solution-state NMR. Biomacromolecules 2015; 16:1614-21. [PMID: 25815624 PMCID: PMC4429494 DOI: 10.1021/acs.biomac.5b00190] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 03/26/2015] [Indexed: 11/30/2022]
Abstract
Starch is a prominent component of the human diet and is hydrolyzed by α-amylase post-ingestion. Probing the mechanism of this process has proven challenging, due to the intrinsic heterogeneity of individual starch granules. By means of solution-state NMR, we demonstrate that flexible polysaccharide chains protruding from the solvent-exposed surfaces of waxy rice starch granules are highly mobile and that during hydrothermal treatment, when the granules swell, the number of flexible residues on the exposed surfaces increases by a factor of 15. Moreover, we show that these flexible chains are the primary substrates for α-amylase, being cleaved in the initial stages of hydrolysis. These findings allow us to conclude that the quantity of flexible α-glucan chains protruding from the granule surface will greatly influence the rate of energy acquisition from digestion of starch.
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Affiliation(s)
- Andrew J. Baldwin
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United
Kingdom
| | - Danielle L. Egan
- Biopolymers
Group, Diabetes and Nutritional Sciences Division, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United
Kingdom
| | - Fredrick
J. Warren
- Biopolymers
Group, Diabetes and Nutritional Sciences Division, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United
Kingdom
| | - Paul D. Barker
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United
Kingdom
| | - Christopher M. Dobson
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United
Kingdom
| | - Peter J. Butterworth
- Biopolymers
Group, Diabetes and Nutritional Sciences Division, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United
Kingdom
| | - Peter R. Ellis
- Biopolymers
Group, Diabetes and Nutritional Sciences Division, King’s College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United
Kingdom
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17
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Grundy MML, Wilde PJ, Butterworth PJ, Gray R, Ellis PR. Impact of cell wall encapsulation of almonds on in vitro duodenal lipolysis. Food Chem 2015; 185:405-12. [PMID: 25952886 PMCID: PMC4430076 DOI: 10.1016/j.foodchem.2015.04.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/12/2015] [Accepted: 04/01/2015] [Indexed: 11/26/2022]
Abstract
Tissue microstructure controlled rate and extent of in vitro lipolysis in almonds. Lipolysis methods using pH-stat and GC analysis were in good agreement. Increasing lipid bioaccessibility led to increased levels of digestibility. Almond cell walls restrict lipid release, thus hindering digestion kinetics.
Although almonds have a high lipid content, their consumption is associated with reduced risk of cardiovascular disease. One explanation for this paradox could be limited bioaccessibility of almond lipids due to the cell wall matrix acting as a physical barrier to digestion in the upper gastrointestinal tract. We aimed to measure the rate and extent of lipolysis in an in vitro duodenum digestion model, using raw and roasted almond materials with potentially different degrees of bioaccessibility. The results revealed that a decrease in particle size led to an increased rate and extent of lipolysis. Particle size had a crucial impact on lipid bioaccessibility, since it is an indicator of the proportion of ruptured cells in the almond tissue. Separated almond cells with intact cell walls showed the lowest levels of digestibility. This study underlines the importance of the cell wall for modulating lipid uptake and hence the positive health benefits underlying almond consumption.
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Affiliation(s)
- Myriam M L Grundy
- King's College London, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, London SE1 9NH, UK.
| | - Peter J Wilde
- Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK.
| | - Peter J Butterworth
- King's College London, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, London SE1 9NH, UK.
| | - Robert Gray
- King's College London, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, London SE1 9NH, UK.
| | - Peter R Ellis
- King's College London, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, London SE1 9NH, UK.
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18
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Grundy MML, Grassby T, Mandalari G, Waldron KW, Butterworth PJ, Berry SEE, Ellis PR. Effect of mastication on lipid bioaccessibility of almonds in a randomized human study and its implications for digestion kinetics, metabolizable energy, and postprandial lipemia. Am J Clin Nutr 2015; 101:25-33. [PMID: 25527747 PMCID: PMC4266890 DOI: 10.3945/ajcn.114.088328] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 10/07/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The particle size and structure of masticated almonds have a significant impact on nutrient release (bioaccessibility) and digestion kinetics. OBJECTIVES The goals of this study were to quantify the effects of mastication on the bioaccessibility of intracellular lipid of almond tissue and examine microstructural characteristics of masticated almonds. DESIGN In a randomized, subject-blind, crossover trial, 17 healthy subjects chewed natural almonds (NAs) or roasted almonds (RAs) in 4 separate mastication sessions. Particle size distributions (PSDs) of the expectorated boluses were measured by using mechanical sieving and laser diffraction (primary outcome). The microstructure of masticated almonds, including the structural integrity of the cell walls (i.e., dietary fiber), was examined with microscopy. Lipid bioaccessibility was predicted by using a theoretical model, based on almond particle size and cell dimensions, and then compared with empirically derived release data. RESULTS Intersubject variations (n = 15; 2 subjects withdrew) in PSDs of both NA and RA samples were small (e.g., laser diffraction; CV: 12% and 9%, respectively). Significant differences in PSDs were found between these 2 almond forms (P < 0.05). A small proportion of lipid was released from ruptured cells on fractured surfaces of masticated particles, as predicted by using the mathematical model (8.5% and 11.3% for NAs and RAs, respectively). This low percentage of lipid bioaccessibility is attributable to the high proportion (35-40%) of large particles (>500 μm) in masticated almonds. Microstructural examination of the almonds indicated that most intracellular lipid remained undisturbed in intact cells after mastication. No adverse events were recorded. CONCLUSIONS Following mastication, most of the almond cells remained intact with lipid encapsulated by cell walls. Thus, most of the lipid in masticated almonds is not immediately bioaccessible and remains unavailable for early stages of digestion. The lipid encapsulation mechanism provides a convincing explanation for why almonds have a low metabolizable energy content and an attenuated impact on postprandial lipemia.
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Affiliation(s)
- Myriam M L Grundy
- From the Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, United Kingdom (MMLG, TG, PJB, SEEB, and PRE); the Institute of Food Research, Norwich Research Park, United Kingdom (GM and KWW); and the Department of Drug Science and Products for Health, University of Messina, Italy (GM)
| | - Terri Grassby
- From the Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, United Kingdom (MMLG, TG, PJB, SEEB, and PRE); the Institute of Food Research, Norwich Research Park, United Kingdom (GM and KWW); and the Department of Drug Science and Products for Health, University of Messina, Italy (GM)
| | - Giuseppina Mandalari
- From the Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, United Kingdom (MMLG, TG, PJB, SEEB, and PRE); the Institute of Food Research, Norwich Research Park, United Kingdom (GM and KWW); and the Department of Drug Science and Products for Health, University of Messina, Italy (GM)
| | - Keith W Waldron
- From the Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, United Kingdom (MMLG, TG, PJB, SEEB, and PRE); the Institute of Food Research, Norwich Research Park, United Kingdom (GM and KWW); and the Department of Drug Science and Products for Health, University of Messina, Italy (GM)
| | - Peter J Butterworth
- From the Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, United Kingdom (MMLG, TG, PJB, SEEB, and PRE); the Institute of Food Research, Norwich Research Park, United Kingdom (GM and KWW); and the Department of Drug Science and Products for Health, University of Messina, Italy (GM)
| | - Sarah E E Berry
- From the Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, United Kingdom (MMLG, TG, PJB, SEEB, and PRE); the Institute of Food Research, Norwich Research Park, United Kingdom (GM and KWW); and the Department of Drug Science and Products for Health, University of Messina, Italy (GM)
| | - Peter R Ellis
- From the Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, United Kingdom (MMLG, TG, PJB, SEEB, and PRE); the Institute of Food Research, Norwich Research Park, United Kingdom (GM and KWW); and the Department of Drug Science and Products for Health, University of Messina, Italy (GM)
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19
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Edwards CH, Warren FJ, Campbell GM, Gaisford S, Royall PG, Butterworth PJ, Ellis PR. A study of starch gelatinisation behaviour in hydrothermally-processed plant food tissues and implications for in vitro digestibility. Food Funct 2015; 6:3634-41. [DOI: 10.1039/c5fo00754b] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Within plant tissues of different particle sizes, the extent of gelatinisation revealed by DSC was related to thein vitrodigestion of encapsulated starch granules.
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Affiliation(s)
- Cathrina H. Edwards
- Biopolymers Group
- Diabetes and Nutritional Sciences Division
- Faculty of Life Sciences and Medicine
- King's College London
- London
| | - Frederick J. Warren
- Biopolymers Group
- Diabetes and Nutritional Sciences Division
- Faculty of Life Sciences and Medicine
- King's College London
- London
| | - Grant M. Campbell
- Satake Centre for Grain Process Engineering
- School of Chemical Engineering and Analytical Science
- University of Manchester
- Manchester
- UK
| | - Simon Gaisford
- Pharmaceutics
- School of Pharmacy
- University College London
- London
- UK
| | - Paul G. Royall
- Drug Delivery Group
- Institute of Pharmaceutical Science
- Faculty of Life Science and Medicine
- King's College London
- London
| | - Peter J. Butterworth
- Biopolymers Group
- Diabetes and Nutritional Sciences Division
- Faculty of Life Sciences and Medicine
- King's College London
- London
| | - Peter R. Ellis
- Biopolymers Group
- Diabetes and Nutritional Sciences Division
- Faculty of Life Sciences and Medicine
- King's College London
- London
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20
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Patel H, Day R, Butterworth PJ, Ellis PR. A mechanistic approach to studies of the possible digestion of retrograded starch by α-amylase revealed using a log of slope (LOS) plot. Carbohydr Polym 2014; 113:182-8. [PMID: 25256473 PMCID: PMC4194354 DOI: 10.1016/j.carbpol.2014.06.089] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 06/23/2014] [Accepted: 06/24/2014] [Indexed: 11/02/2022]
Abstract
The rate and extent of digestibility of starch were analysed using the logarithm of the slope (LOS) method. Digestibility curves with α-amylase were obtained for starches in their native, gelatinised and 24h retrograded form. A LOS plot of the digestibility curves was then constructed, which allowed the rate constant (k) and the concentration of the product at the end of the reaction (C∞) to be calculated. It also allowed the identification of rapid and slow phases in starch digestion. Upon gelatinisation, both k and C∞ increased with dramatic changes notably in C∞; however after starch samples had been stored for 24h at room temperature, k was not affected but C∞ decreased. This suggests that retrograded starch is virtually inert to amylase action. Both k and C∞ were strongly related to the increase in degree of order of the α-glucan chains, monitored by FTIR-ATR spectroscopy, in retrograded starch.
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Affiliation(s)
- Hamung Patel
- King's College London, School of Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150, Stamford Street, London SE1 9NH, UK
| | - Richard Day
- King's College London, School of Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150, Stamford Street, London SE1 9NH, UK
| | - Peter J Butterworth
- King's College London, School of Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150, Stamford Street, London SE1 9NH, UK
| | - Peter R Ellis
- King's College London, School of Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150, Stamford Street, London SE1 9NH, UK.
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21
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Edwards CH, Warren FJ, Milligan PJ, Butterworth PJ, Ellis PR. A novel method for classifying starch digestion by modelling the amylolysis of plant foods using first-order enzyme kinetic principles. Food Funct 2014; 5:2751-8. [DOI: 10.1039/c4fo00115j] [Citation(s) in RCA: 157] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
LOS plots of first-order digestibility data enable the rapid identification of nutritionally-important starch fractions, and allow the final extent (C∞) of starch amylolysis to be accurately predicted.
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Affiliation(s)
- Cathrina H. Edwards
- Biopolymers Group
- Diabetes and Nutritional Sciences Division
- School of Medicine
- King's College London
- London, UK
| | - Frederick J. Warren
- Biopolymers Group
- Diabetes and Nutritional Sciences Division
- School of Medicine
- King's College London
- London, UK
| | - Peter J. Milligan
- Biopolymers Group
- Diabetes and Nutritional Sciences Division
- School of Medicine
- King's College London
- London, UK
| | - Peter J. Butterworth
- Biopolymers Group
- Diabetes and Nutritional Sciences Division
- School of Medicine
- King's College London
- London, UK
| | - Peter R. Ellis
- Biopolymers Group
- Diabetes and Nutritional Sciences Division
- School of Medicine
- King's College London
- London, UK
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22
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Warren FJ, Butterworth PJ, Ellis PR. The surface structure of a complex substrate revealed by enzyme kinetics and Freundlich constants for α-amylase interaction with the surface of starch. Biochim Biophys Acta Gen Subj 2013; 1830:3095-101. [DOI: 10.1016/j.bbagen.2012.12.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 11/21/2012] [Accepted: 12/21/2012] [Indexed: 01/10/2023]
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23
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Warren FJ, Perston BB, Royall PG, Butterworth PJ, Ellis PR. Infrared spectroscopy with heated attenuated total internal reflectance enabling precise measurement of thermally induced transitions in complex biological polymers. Anal Chem 2013; 85:3999-4006. [PMID: 23461675 DOI: 10.1021/ac303552s] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report an improved tool for acquiring temperature-resolved fourier transform infrared (FT-IR) spectra of complex polymer systems undergoing thermal transitions, illustrated by application to several phenomena related to starch gelatinization that have proved difficult to study by other means. Starch suspensions from several botanical origins were gelatinized using a temperature-controlled attenuated total reflectance (ATR) crystal, with IR spectra collected every 0.25 °C. By following the 995/1022 cm(-1) peak ratio, clear transitions occurring between 59 and 70 °C were observed, for which the midpoints could be determined accurately by sigmoidal fits. The magnitude of the change in peak ratio was found to be strongly correlated to the enthalpy of gelatinization as measured by differential scanning calorimetry (DSC, R(2) = 0.988). An important advantage of the technique, compared to DSC, is that the signal-to-noise ratio is not reduced when measuring very broad transitions. This has the potential to allow more precise determination of the gelatinization parameters of high-amylose starches, for which gelatinization may take place over several tens of °C.
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Affiliation(s)
- Frederick J Warren
- King's College London, School of Medicine, Diabetes and Nutritional Sciences Division, Biopolymers Group, London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom
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Warren FJ, Butterworth PJ, Ellis PR. Studies of the effect of maltose on the direct binding of porcine pancreatic α-amylase to maize starch. Carbohydr Res 2012; 358:67-71. [DOI: 10.1016/j.carres.2012.07.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 07/04/2012] [Accepted: 07/05/2012] [Indexed: 11/15/2022]
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Warren FJ, Royall PG, Butterworth PJ, Ellis PR. Immersion mode material pocket dynamic mechanical analysis (IMP-DMA): a novel tool to study gelatinisation of purified starches and starch-containing plant materials. Carbohydr Polym 2012; 90:628-36. [PMID: 24751086 DOI: 10.1016/j.carbpol.2012.05.088] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/13/2012] [Accepted: 05/22/2012] [Indexed: 11/27/2022]
Abstract
There is a clear need for improved methods for the study of the physical changes that occur in slurries and sol-gel systems that have significant water content. In this paper a novel immersion mode material pocket form of dynamic mechanical analysis (IMP-DMA) has been designed, combining material pocket technology to provide physical support to a powdered sample within an immersion bath. IMP-DMA allows the mechanical response of a powder during heating to be monitored in excess water. IMP-DMA was evaluated using a range of starch samples loaded as a slurry into a solid steel pocket, the mechanical responses of these samples were monitored as a function of temperature, and values for modulus and tanδ peaks were found to correspond well with events occurring at both the onset and peak gelatinisation temperatures as measured by differential scanning calorimetry (DSC) (e.g. wheat starch has an onset and peak DSC temperature of 49.3 °C and 57.2 °C, respectively, and shows a peak in tanδ at 52.8 °C and a modulus peak at 57.7 °C). Some limitations were found in the ability of DMA to detect transitions in starches with low or high amylose contents. IMP-DMA was shown to be an effective tool for monitoring the changes in starch structure that occur during gelatinisation, both in purified starches and in more complex starch-containing food materials. Thus, a new hyphenated form of DMA is now available that permits the thermally induced transitions of particle water dispersions to be characterised.
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Affiliation(s)
- Frederick J Warren
- King's College London, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom
| | - Paul G Royall
- King's College London, Institute of Pharmaceutical Science, Drug Delivery Group, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom
| | - Peter J Butterworth
- King's College London, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom
| | - Peter R Ellis
- King's College London, Diabetes and Nutritional Sciences Division, Biopolymers Group, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, United Kingdom
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Naziroğlu M, Butterworth PJ, Sonmez TT. Dietary vitamin C and E modulates antioxidant levels in blood, brain, liver, muscle, and testes in diabetic aged rats. INT J VITAM NUTR RES 2012; 81:347-57. [PMID: 22673918 DOI: 10.1024/0300-9831/a000083] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
While tissue dysfunction is a well-recognized consequence of diabetes mellitus in aged people, the underlying mechanisms are poorly understood. Daily (VCE) supplementation of vitamins C and E can be beneficial to diabetic aged animals in reducing free radical production. The aim of this study was to investigate whether dietary VCE supplementation modulates oxidative stress and antioxidant redox systems in streptozotocin (STZ)-induced aged diabetic rats. Thirty aged rats (18 - 20 months) were randomly divided into three groups. The first group acted as a control and the second group was diabetic. VCE-supplemented feed was given to aged, diabetic rats, constituting the third group. Diabetes was induced using a single dose of intraperitoneal STZ. On the 21(st) day after STZ dosage, blood and tissue samples were taken from all animals. Glutathione peroxidase activity in liver, erythrocytes, muscle, and testes; catalase activity in plasma and erythrocytes; reduced glutathione levels in plasma; vitamin E concentration in plasma, liver, and muscle; b-carotene concentration in brain; and high-density lipoprotein (HDL)-cholesterol levels in plasma were lower in the diabetic group than in the control group. Lipid peroxidation (LP) levels in plasma, liver, brain, and muscle, and alanine aminotransferase (ALT), aspartate aminotransferase (AST), triacyglycerols, and total and low-density lipoprotein (LDL)-cholesterol values in plasma were higher in the diabetic group than in the control group. The LP, enzyme, vitamin, and lipid profile values levels were mostly restored by VCE treatment. Liver and testis weights did not change by diabetic status and VCE supplementation, although body weight was lower in the diabetic group than in the control group. In conclusion, brain, liver, and testes tissues seem most sensitive in aged diabetic rats to oxidative stress. We observed that VCE supplementation relieves oxidative stress in the blood and tissues of diabetic aged rats by modulating the antioxidant system and lipid profile.
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Affiliation(s)
- Mustafa Naziroğlu
- Department of Biophysics, Medical Faculty, Suleyman Demirel University, Isparta, Turkey.
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27
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Ellis PR, Grundy M, Grassby T, Mandalari G, Faulks RM, Berry SE, Waldron KW, Butterworth PJ. The role of dietary fiber in regulating lipid bioaccessibility of almonds during mastication. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.1015.4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Peter R Ellis
- School of MedicineKing's College LondonLondonUnited Kingdom
| | - Myriam Grundy
- School of MedicineKing's College LondonLondonUnited Kingdom
| | - Terri Grassby
- School of MedicineKing's College LondonLondonUnited Kingdom
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Butterworth PJ, Warren FJ, Edwards CH, Grassby T, Patel H, Ellis PR. How analysis of data from alpha‐amylase catalysed starch digestibility performed
in vitro
contributes to an understanding of rates and extent of digestion starchy foods
in vivo. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.638.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - Terri Grassby
- School of MedicineKing's College LondonLondonUnited Kingdom
| | - Hamung Patel
- School of MedicineKing's College LondonLondonUnited Kingdom
| | - Peter R. Ellis
- School of MedicineKing's College LondonLondonUnited Kingdom
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Warren FJ, Royall PG, Gaisford S, Butterworth PJ, Ellis PR. Binding interactions of α-amylase with starch granules: The influence of supramolecular structure and surface area. Carbohydr Polym 2011. [DOI: 10.1016/j.carbpol.2011.05.062] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Tahir R, Ellis PR, Bogracheva TY, Meares-Taylor C, Butterworth PJ. Study of the structure and properties of native and hydrothermally processed wild-type, lam and r variant pea starches that affect amylolysis of these starches. Biomacromolecules 2011; 12:123-33. [PMID: 21158380 DOI: 10.1021/bm101070r] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Starches from WT, lam, and r pea mutants differing in amylopectin/amylose contents (70, 90, and 28% amylopectin, respectively) were used in kinetic studies of pancreatic α-amylase action at 37 °C and for investigations of their supramolecular structure and physicochemical properties during heating. For WT and lam starches, amylase accessibility and catalytic efficiencies (CE) increased following hydrothermal processing up to 100 °C. Accessibility changed relatively less in r during heating with increasing K(m) between 60-90 °C. Limiting values of K(m) after gelatinization were very similar for all three mutants, indicating that relative proportions of amylose/amylopectin have little influence on amylase accessibility once ordered structures are lost. For WT and lam, increases in enzyme accessibility and CE paralleled a rise in amorphous content. It is suggested that the complex behavior for r resulted from amylose gel formation between 60-90 °C. Amorphous amylopectin seems a better substrate for amylase than amorphous amylose.
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Affiliation(s)
- Rumana Tahir
- Department of Biochemistry, Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, Franklin Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom
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33
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Tahir R, Ellis PR, Butterworth PJ. The relation of physical properties of native starch granules to the kinetics of amylolysis catalysed by porcine pancreatic α-amylase. Carbohydr Polym 2010. [DOI: 10.1016/j.carbpol.2010.01.055] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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34
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Nazıroğlu M, Kutluhan S, Uğuz AC, Çelik Ö, Bal R, Butterworth PJ. Topiramate and Vitamin E Modulate the Electroencephalographic Records, Brain Microsomal and Blood Antioxidant Redox System in Pentylentetrazol-Induced Seizure of Rats. J Membr Biol 2009; 229:131-40. [DOI: 10.1007/s00232-009-9177-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 05/20/2009] [Indexed: 12/15/2022]
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35
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Roder N, Gerard C, Verel A, Bogracheva TY, Hedley CL, Ellis PR, Butterworth PJ. Factors affecting the action of α-amylase on wheat starch: Effects of water availability. An enzymic and structural study. Food Chem 2009. [DOI: 10.1016/j.foodchem.2008.07.106] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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36
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Naziroğlu M, Butterworth PJ. Protective Effects of Moderate Exercise With Dietary Vitamin C and E on Blood Antioxidative Defense Mechanism in Rats With Streptozotocin-Induced Diabetes. ACTA ACUST UNITED AC 2005; 30:172-85. [PMID: 15981786 DOI: 10.1139/h05-113] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Daily moderate exercise and supplementation of vitamins C and E (VCE) can be beneficial in diabetes by ameliorating the effects of free radical production. The present study sought to analyze the effect of moderate exercise accompanying VCE supplementation on lipid peroxidation (LP) and antioxidative systems in the blood of streptozotocin-induced diabetic rats. Forty female Wistar rats were randomly divided 4 groups. The 1st and 2nd groups served as the control and diabetic groups, respectively. The 3rd group was the diabetic-exercise group. The 4th group, also diabetic-exercise rats, received VCE-supplemented feed. Animals in the exercised groups were moderately exercised on a treadmill 5 days a week for 3 weeks. Diabetes was induced on Day 0 of the exercise. Plasma and red blood cell (RBC) samples were taken from all animals on Day 20. Glutathione peroxidase, catalase, and reduced glutathione levels in plasma and RBCs, and vitamins A, E, and β-carotene in plasma were lower in diabetic rats than in control animals, whereas there was a significant increase in platelet counts in both plasma and RBC LP levels. The decreased antioxidant enzymes and vitamins, and the increased LP levels and WBC counts, did improve through exercise only, although their levels were mostly increased by exercise + VCE supplementation. There were no significant changes in the hemoglobin and hematocrit values in the 4 groups. In conclusion, these data demonstrate an increase in LP in the blood of diabetic animals whereas there was a decrease in the antioxidant vitamins and enzymes. However, dietary VCE with moderate exercise may strengthen the antioxidant defense system by decreasing reactive oxygen species. Key words: hyperglycemia, glutathione peroxidase, oxidative stress, hematological values
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Affiliation(s)
- Mustafa Naziroğlu
- Dept. of Physiology, Veterinary Faculty, Firat University, Elaziğ, TR-23 119 Turkey
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37
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Slaughter SL, Ellis PR, Jackson EC, Butterworth PJ. The effect of guar galactomannan and water availability during hydrothermal processing on the hydrolysis of starch catalysed by pancreatic alpha-amylase. Biochim Biophys Acta 2002; 1571:55-63. [PMID: 12031290 DOI: 10.1016/s0304-4165(02)00209-x] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The effects of water-soluble nonstarch polysaccharides (sNSP) on human metabolism are considered to be beneficial because they decrease postprandial glycaemia and insulinaemia following ingestion of starch-rich foods. The mechanisms by which sNSP attenuate the postprandial rise in blood glucose are not well understood but their presence increases the viscosity of gastrointestinal contents, which affects physiological functions, e.g. gastric emptying and peristalsis. Increased viscosity and decreased water activity during hydrothermal treatment of starch could influence alpha-amylase action. Using guar galactomannan as a representative of sNSP, we found that galactomannan has a direct noncompetitive inhibitory effect on alpha-amylase with a K(i) value of approximately 0.5% (3.3 microM). The inhibition is not time dependent and studies suggest direct binding of the enzyme to galactomannan; the resulting galactomannan-amylase complex being inactive. Processing of starch at low water levels greatly affects the catalytic efficiency of alpha-amylase. The Km value for starch heat treated in limited water is raised and kcat is lowered relative to starch gelatinised in excess water. Since galactomannan has no effect on the Km of alpha-amylase, we conclude that the inhibitory action of the polymer is not secondary to a decrease in available water. Neither does it seem to be a consequence of impaired diffusion of enzyme, substrate and products because of an increase in viscosity of the medium.Thus, the effects of sNSP in lowering postprandial glycaemia not only involve modifications of gut physiology, but also include direct inhibition of the first stage in the biochemical degradation of starch.
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Affiliation(s)
- Suzanne L Slaughter
- Biopolymers Group, Division of Life Sciences, King's College London, Franklin-Wilkins Building, London, UK
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38
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Slaughter SL, Ellis PR, Butterworth PJ. An investigation of the action of porcine pancreatic alpha-amylase on native and gelatinised starches. Biochim Biophys Acta 2001; 1525:29-36. [PMID: 11342250 DOI: 10.1016/s0304-4165(00)00162-8] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The action of pancreatic alpha-amylase (EC 3.2.1.1) on various starches has been studied in order to achieve better understanding of how starch structural properties influence enzyme kinetic parameters. Such studies are important in seeking explanations for the wide differences reported in postprandial glycaemic and insulinaemic indices associated with different starchy foodstuffs. Using starches from a number of different sources, in both native and gelatinised forms, as substrates for porcine alpha-amylase, we showed by enzyme kinetic studies that adsorption of amylase to starch is of kinetic importance in the reaction mechanism, so that the relationship between reaction velocity and enzyme concentration [E0] is logarithmic and described by the Freundlich equation. Estimations of catalytic efficiencies were derived from measurements of kcat/Km performed with constant enzyme concentration so that comparisons between different starches were not complicated by the logarithmic relationship between E0 and reaction velocity. Such studies reveal that native starches from normal and waxy rice are slightly better substrates than those from wheat and potato. After gelatinisation at 100 degrees C, kcat/Km values increased by 13-fold (waxy rice) to 239-fold (potato). Phosphate present in potato starch may aid the swelling process during heating of suspensions; this seems to produce a very favourable substrate for the enzyme. Investigation of pre-heat treatment effects on wheat starch shows that the relationship between treatment and kcat/Km is not a simple one. The value of kcat/Km rises to reach a maximum at a pre-treatment temperature of 75 degrees C and then falls sharply if the treatment is conducted at higher temperatures. It is known that amylose is leached from starch granules during heating and dissolves. On cooling, the dissolved starch is likely to retrograde and become resistant to amylolysis. Thus the catalytic efficiency tends to fall. In addition, we find that the catalytic efficiency on the different starches varies inversely with their solubility and we interpret this finding on the assumption that the greater the solubility, the greater is the likelihood of retrogradation. We conclude that although alpha-amylase is present in high activity in digestive fluid, the enzymic hydrolysis of starch may be a limiting factor in carbohydrate digestion because of factors related to the physico-chemical properties of starchy foods.
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Affiliation(s)
- S L Slaughter
- Biopolymers Group, Division of Life Sciences, King's College London, Franklin-Wilkins Building, 150 Stamford St., SE1 8WA, London, UK
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39
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Jünemann S, Butterworth PJ, Wrigglesworth JM. A suggested mechanism for the catalytic cycle of cytochrome bd terminal oxidase based on kinetic analysis. Biochemistry 1995; 34:14861-7. [PMID: 7578096 DOI: 10.1021/bi00045a029] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The apparent oxygen affinity of cytochrome bd from Escherichia coli and Azotobacter vinelandii has been measured using oxymyoglobin as a sensitive monitor of oxygen concentration. In membrane preparations, the Km(O2) and respiratory rate varied with the nature of the primary substrate used (malate, lactate, reduced nicotinamide adenine dinucleotide (NADH), or ubiquinol-1). At maximum respiratory rates, the Km(O2) for cytochrome bd from A. vinelandii was 4.1 microM, approximately 2 times higher than the corresponding value for the E. coli enzyme. There were no significant differences between the Km(O2) values for membrane-bound and purified cytochrome bd from A. vinelandii when ubiquinol-1 was used as primary substrate. The kinetic parameters Km(O2) and Vmax provide a value of 2.8 x 10(8) M-1 s-1 for the bimolecular rate constant for oxygen reaction with the enzyme, suggesting that this reaction is diffusion-controlled. Kinetic analysis indicates a mechanism involving a ternary complex. A scheme for the reaction mechanism of cytochrome bd is proposed.
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Affiliation(s)
- S Jünemann
- Biochemistry Section, King's College London, UK
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40
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Butterworth PJ. Time-dependent irreversible inhibition of bovine kidney alkaline phosphatase by oxidized adenosine. Use of this compound as a site-directed inhibitor for studying uncompetitive inhibition. Cell Biochem Funct 1994; 12:263-6. [PMID: 7834815 DOI: 10.1002/cbf.290120406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The L/B/K type of mammalian alkaline phosphatase (ALP) is inhibited uncompetitively by nucleotides. A combination of adenosine and nicotinamide is more effective than either adenosine or nicotinamide alone, probably because a dinucleotide structure is necessary to trigger a conformational change accompanying binding of structures such as NADH. It has been suggested that a loop region containing residue 429 in the ALP polypeptide is important in the interaction of uncompetitive inhibitors with the enzyme. In the L/B/K isoenzyme, residue 429 is a histidine and is a potential target for modification. In an attempt to learn more about the molecular events accompanying inhibition of ALP by uncompetitive inhibitors, bovine kidney ALP was reacted with oxidized adenosine in the presence of nicotinamide to see if site-directed modification occurs. Kidney ALP was irreversibly inactivated by oxidized adenosine but the reaction was slow. The site modified is likely to be close to the region of binding. Sequence data for the kidney enzyme shows that in the region of residue 429 there are no residues except His429 itself that is likely to react with oxidized adenosine.
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Affiliation(s)
- P J Butterworth
- Department of Biochemistry, School of Life Sciences, King's College London, U.K
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41
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Younus MJ, Jouhal K, Butterworth PJ. Inhibition by cyclic AMP and phorbol esters of sodium-dependent uptake of phosphate by rat hepatocytes. Biochim Biophys Acta 1994; 1190:444-8. [PMID: 8142448 DOI: 10.1016/0005-2736(94)90106-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Na(+)-dependent phosphate uptake by rat hepatocytes in primary culture is inhibited in a time-dependent fashion by cyclic AMP and by the myristate, acetate ester of phorbol. After incubation for 15 min at 37 degrees C with 10(-7) M dibutyryl cAMP, the Vmax of transport is decreased from 0.52 to 0.23 nmol Pi/min per mg protein but the Km value of approximately 1 mM is hardly affected by the treatment. Thus, physiological control of Pi uptake by liver cells probably involves protein phosphorylation(s) catalysed by protein kinases. Protein kinase C may be important but the relatively high concentration of phorbol ester needed to cause inhibition of transport is not convincing evidence for protein kinase C involvent. In the presence of fructose, the rate of Pi uptake is decreased by 50%. This effect is probably secondary to a depletion of cellular ATP.
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Affiliation(s)
- M J Younus
- Department of Biochemistry, King's College, London, UK
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42
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Abstract
Plasma membrane fractions were prepared from homogenates of rat liver by density gradient centrifugation and then used for the formation of right-side-out vesicles. Uptake of Pi into the vesicles is rapid when an inwardly directed sodium gradient is present and an overshoot of uptake occurs indicative of accumulation against a Pi concentration gradient. Initial Pi uptake rate in the presence of a K+ gradient is approx half that seen with Na+, but uptake in the presence of a choline chloride gradient is very slow. An overshoot does not occur with either K+ or choline gradients. The Km(Pi) for the Na-dependent component of Pi uptake is approx. 1 mM and Vmax at 20 degrees C is 0.8 nmol/min per mg protein. The relationship between initial uptake rate and Na+ concentration is sigmoid, with a Hill coefficient of 2.6. It is concluded that the cotransporter resembles that of kidney and intestine in possessing at least two interacting sites for Na+ and that in intact cells the Na+ gradient maintained by the sodium pump ATPase provides the energy for accumulation of Pi against the unfavourable membrane potential.
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Affiliation(s)
- M J Younus
- Department of Biochemistry, King's College, London, UK
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Butterworth PJ, Younus MJ. Uptake of phosphate by rat hepatocytes in primary culture: a sodium-dependent system that is stimulated by insulin. Biochim Biophys Acta 1993; 1148:117-22. [PMID: 8499458 DOI: 10.1016/0005-2736(93)90167-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Primary cultures of rat hepatocytes take up phosphate by a saturable Na(+)-dependent process. Thus the plasma membrane possesses an N(+)-Pi cotransporter of the type described for many cell types, e.g., kidney proximal tubular cells and enterocytes. Coupling to Na+ overcomes the barrier to anion entry represented by the membrane potential. At 0.12 mM Pi, the effect of Na+ is cooperative with a Hill coefficient of 1.7 suggesting two sodium sites per molecule of carrier. At 37 degrees C, the Km (for Pi) and Vmax for the sodium-dependent fraction of Pi uptake are approx. 1 mM and 0.35 nmol Pi/min per mg cell protein, respectively. Insulin stimulates Vmax four-fold with no significant effect on Km. Pi uptake in the absence of sodium is not affected by insulin. The stimulation by insulin could be of metabolic significance. Glucose phosphorylation at the expense of ATP is raised in liver following insulin stimulation, and thus, initially there may be an increased demand for Pi for oxidative phosphorylation until new steady-state conditions of hexose phosphate concentrations and of ATP turnover become established.
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Abstract
ADPase has been purified from bovine spleen. Electrophoresis revealed a minor contaminent in the preparation that may represent ADPase that has been decreased in size by limited proteolysis during extraction and purification. The native enzyme behaves on SDS/PAGE as a 100-kDa protein but ADPase is a glycoprotein and so its electrophoretic behaviour may be anomalous. The apparent molecular mass is decreased to 70 kDa after removal of carbohydrate by treatment with a glycosidase. The use of a cross-linking reagent followed by electrophoresis suggests that the enzyme is composed of a single subunit. The specific activity of the purified material was 115 U/mg protein. The enzyme catalyses the hydrolysis of nucleoside di- and tri-phosphates but nucleoside monophosphates are not acted upon. The Km for ADP (approx. 10-15 microM) is unaffected by the state of purification of the enzyme, but catalytic activity of the purified material is stimulated by inclusion of detergent in the assay system and by calcium ions. Maximum activity is seen at pH 8.0-8.5 with ADP as substrate but the optimum shifts to 7.5-8.0 for ATP hydrolysis.
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Affiliation(s)
- F D Moodie
- Department of Biochemistry, King's College, London, England
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45
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Abstract
Efflux of Pi from rat hepatocytes suspended in phosphate free-medium was studied by chemical assay of released Pi and by monitoring the loss in radioactivity of cells pre-labelled with [32P]-Pi. The release follows first-order kinetics fairly closely with a rate constant of 7 x 10(-3) min-1 approximately. Insulin at a concentration of 10(-8) M had no effect on the rate of Pi release and it is concluded therefore, that the insulin-stimulated accumulation of Pi described in the literature is the result of hormone action on Pi uptake by liver rather than on its release.
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Affiliation(s)
- M Parkash
- Department of Biochemistry, King's College London, UK
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46
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Affiliation(s)
- P G Atkinson
- Department of Biochemistry, King's College, London, U.K
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Pollard JW, Jahan M, Butterworth PJ. Characterization and expression of uterine and placental alkaline phosphatases in the mouse. J Reprod Fertil 1990; 89:735-42. [PMID: 1698226 DOI: 10.1530/jrf.0.0890735] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Alkaline phosphatase (ALP) is rapidly induced in the uterine subepithelial stroma after a natural or artificial decidual stimulus. During gestation ALP-specific activity peaked at Day 7 to 8 (Day 1 is day of detection of the copulation plug) followed by a rapid decline to control levels by Day 9. This elevation in enzyme activity was preceded by an 8-fold induction of a 2.6 kilobase (kb) mRNA. This mRNA was not preferentially localized to implantation sites. ALP activity was detected in the placenta at Day 9 and reached maximum specific activity at Day 19. The placental ALP was also encoded by a 2.6 kb mRNA. Uterine and placental ALPs were inhibited to the same extent by levamisole, L-tryptophan and homoarginine. The calculated Ki values for these inhibitors were not statistically different between the uterine and placental forms. Km values towards the substrate p-nitrophenylphosphate, however, were statistically different between the uterine and placental forms. Both uterine and placental ALPs were stimulated 3-4-fold by addition of 2 mM-Mg2+. Electrophoretic mobilities on SDS polyacrylamide gel, where the enzyme migrated as a single band, were the same. The uterine form, however, could be distinguished from the placental isoenzyme by separation on non-denaturing polyacrylamide gels; the uterine form had a single zone of activity which migrated with an intermediate mobility between the two zones of activity detected for the placental enzyme. These differences in mobility could be ascribed to the sialic acid content of the enzyme because treatment with neuraminidase resulted in the uterine and placental forms migrating with comparable but slower mobilities in non-denaturing gels.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J W Pollard
- Department of Developmental Biology and Cancer, Albert Einstein College of Medicine, Bronx, NY 10461
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Nakagawa T, Butterworth PJ. Studies of the regulation of renal gluconeogenesis in normal and Pi depleted proximal tubule cells. Cell Biochem Funct 1990; 8:31-8. [PMID: 2340630 DOI: 10.1002/cbf.290080106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Pi depletion of proximal tubule cells isolated from mouse kidney results in a decrease in the cell content of fructose-2,6-bisphosphate and an increase in the rate of gluconeogenesis from pyruvate, malate and succinate. Gluconeogenesis from glycerol is unaffected by Pi depletion. Introduction of fructose-2,6-bisphosphate into the cytosol of ATP-permeabilized cells is accompanied by a fall in gluconeogenesis. The presence of external Ca2+ stimulates gluconeogenesis. When cytosolic Ca2+ is raised to 1.8 microM by permeabilization, the resealed cells still require 2.5 mM Ca2+ in the bathing medium in order to perform gluconeogenesis at the maximum rate. Cells permeabilized in the presence of cAMP show a decreased rate of glucose production. Phorbol ester stimulates gluconeogenesis provided that the phorbol treatment is performed in the absence of Ca2+ ions. It is suggested that Pi depletion may stimulate pyruvate carboxylase activity and facilitate the entry of certain gluconeogenic substrates into mitochondria. It is also proposed that important aspects of the control of renal gluconeogenesis by parathyroid hormone are mediated by protein kinase C.
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Affiliation(s)
- T Nakagawa
- Department of Biochemistry, King's College, London, U.K
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Abstract
Characterization of the phosphate transport system across the basolateral membrane of renal proximal tubule has been attempted using isolated proximal tubule cells prepared from chicks. The Pi efflux system is independent of Na+ ions and is not influenced by the nature of the chief anion present in the bathing medium. Pi efflux is not sensitive to DIDS and it is concluded that a generalized anion transporter of band III type is not the chief agent for facilitating Pi exit from the cell across the basolateral membrane. Inhibition of efflux by vanadate is evidence for a specific carrier protein in the membrane. The carrier probably possesses thiol group(s) that are essential for activity. The carrier may effect electroneutral transport of Pi possibly in exchange for OH- ions. The activity of the transport process is not stimulated by depleting the cells of phosphate or inhibited by rearing the chicks on a vitamin D-deficient diet. The system is unlikely to be of great importance for the expression of various regulatory mechanisms that act on the kidney to control the excretion of Pi. The activity declines as the chicks mature however.
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Affiliation(s)
- S Myint
- Department of Biochemistry, King's College (KQC), London, U.K
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Yarleque A, Campos S, Escobar E, Lazo F, Sanchez N, Hyslop S, Marsh NA, Butterworth PJ, Price RG. Isolation and characterization of a fibrinogen-clotting enzyme from venom of the snake, Lachesis muta muta (Peruvian bushmaster). Toxicon 1989; 27:1189-97. [PMID: 2617537 DOI: 10.1016/0041-0101(89)90027-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A fibrinogen-clotting enzyme from the venom of the Peruvian bushmaster snake was purified to homogeneity by gel filtration on Sephadex G-100 followed by DEAE-cellulose ion-exchange chromatography using a linear ionic strength gradient with NaCl. The specific activity of the enzyme was 866 NIH U/mg, representing a 55-fold purification, with a recovery of 45%. The amino acid composition was Asx30, Thr14, Ser15, Glx33, Pro23, Gly22, Ala15, Val22, Cys18, Met3, Ile18, Leu23, Tyr2, Phe13, His8, Lys11, Arg11. The total carbohydrate content was 13.4%, comprised of 3.4% hexose, 8.7% hexosamine and 1.3% sialic acid. The enzyme was active against the synthetic amide substrate alpha-N-benzoyl-DL-arginine-p-nitroanilide (BAPNA) and against the ester substrates alpha-N-benzoyl-L-arginine ethyl ester (BAEE) and tosyl-L-arginine methyl ester (TAME). Kinetic parameters for TAME esterolysis were: Vmax, 135 mumoles/min/mg and Km, 2.5 x 10(-4) M. The pH optimum was 8.0. Vmax for BAPNA amidolysis was 0.363 mumoles/min/mg and Km, 7.5 x 10(-5) M. Enzyme activity was reduced by diethylpyrocarbonate and by photo-oxidation, suggesting that the enzyme is a serine protease with a histidine residue involved in the active site. The enzyme released fibrinopeptide A rapidly from purified human fibrinogen and fibrinopeptide B more slowly. Factor XIII was not activated and the clotting activity was not inhibited by heparin. A dose of 50 micrograms/kg brought about defibrinogenation in anaesthetized rats but rabbits were unaffected. A dose of 80 micrograms/kg defibrinogenated conscious rats after 5 hr. There were no hypotensive or haemorrhagic effects.
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Affiliation(s)
- A Yarleque
- Faculdad de Ciencias Biologicas, Universidad Nacional Mayor de San Marcos, Lima, Peru
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