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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: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [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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Borah PK, Sarkar A, Duary RK. Water-soluble vitamins for controlling starch digestion: Conformational scrambling and inhibition mechanism of human pancreatic α-amylase by ascorbic acid and folic acid. Food Chem 2019; 288:395-404. [DOI: 10.1016/j.foodchem.2019.03.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 03/07/2019] [Accepted: 03/07/2019] [Indexed: 12/11/2022]
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3
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Guo L, Cui B. The Role of Chain Structures on Enzymatic Hydrolysis of Potato and Sweet Potato Amylopectins. STARCH-STARKE 2018. [DOI: 10.1002/star.201800003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Li Guo
- School of Food Sciences and Engineering, Qilu University of Technology (Shandong Academy of Sciences); Jinan 250353 China
| | - Bo Cui
- School of Food Sciences and Engineering, Qilu University of Technology (Shandong Academy of Sciences); Jinan 250353 China
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4
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Mestres C, Bettencourt MDJC, Loiseau G, Matignon B, Grabulos J, Achir N. Modeling cereal starch hydrolysis during simultaneous saccharification and lactic acid fermentation; case of a sorghum-based fermented beverage, gowé. Food Res Int 2017; 100:102-111. [PMID: 28873668 DOI: 10.1016/j.foodres.2017.06.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 06/20/2017] [Accepted: 06/25/2017] [Indexed: 11/24/2022]
Abstract
Gowé is an acidic beverage obtained after simultaneous saccharification and fermentation (SSF) of sorghum. A previous paper focused on modeling the growth of lactic acid bacteria during gowé processing. This paper focuses on modeling starch amylolysis to build an aggregated SSF model. The activity of α-amylase was modeled as a function of temperature and pH, and the hydrolysis rates of both native and soluble starch were modeled via a Michaelis-Menten equation taking into account the maltose and glucose inhibition constants. The robustness of the parameter estimators was ensured by step by step identification in sets of experiments conducted with different proportions of native and gelatinized starch by modifying the pre-cooking temperature. The aggregated model was validated on experimental data and showed that both the pre-cooking and fermentation parameters, particularly temperature, are significant levers for controlling not only acid and sugar contents but also the expected viscosity of the final product. This generic approach could be used as a tool to optimize the sanitary and sensory quality of fermentation of other starchy products.
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Affiliation(s)
- Christian Mestres
- CIRAD, UMR Qualisud TA B-95/16, 73 rue Jean-François Breton, F-34398 Montpellier Cedex 5, France.
| | | | - Gérard Loiseau
- Montpellier SupAgro, UMR Qualisud, 1101 Avenue Agropolis, F-34398 Montpellier Cedex 5, France
| | - Brigitte Matignon
- CIRAD, UMR Qualisud TA B-95/16, 73 rue Jean-François Breton, F-34398 Montpellier Cedex 5, France
| | - Joël Grabulos
- CIRAD, UMR Qualisud TA B-95/16, 73 rue Jean-François Breton, F-34398 Montpellier Cedex 5, France
| | - Nawel Achir
- Montpellier SupAgro, UMR Qualisud, 1101 Avenue Agropolis, F-34398 Montpellier Cedex 5, France
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5
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Warren FJ, Zhang B, Waltzer G, Gidley MJ, Dhital S. The interplay of α-amylase and amyloglucosidase activities on the digestion of starch in in vitro enzymic systems. Carbohydr Polym 2014; 117:192-200. [PMID: 25498625 DOI: 10.1016/j.carbpol.2014.09.043] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/08/2014] [Accepted: 09/08/2014] [Indexed: 11/25/2022]
Abstract
In vitro hydrolysis assays are a key tool in understanding differences in rate and extent of digestion of starchy foods. They offer a greater degree of simplicity and flexibility than dynamic in vitro models or in vivo experiments for quantifiable, mechanistic exploration of starch digestion. In the present work the influence of α-amylase and amyloglucosidase activities on the digestion of maize and potato starch granules was measured using both glucose and reducing sugar assays. Data were analysed through initial rates of digestion, and by 1st order kinetics, utilising logarithm of slope (LOS) plots. The rate and extent of starch digestion was dependent on the activities of both enzymes and the type of starch used. Potato required more enzyme than maize to achieve logarithmic reaction curves, and complete digestion. The results allow targeted design of starch digestion experiments through a thorough understanding of the contributions of α-amylase and amyloglucosidase to digestion rates.
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Affiliation(s)
- Frederick J Warren
- Centre for Nutrition and Food Sciences, ARC Centre of Excellence in Plant Cell Walls, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Brisbane 4072, QLD, Australia
| | - Bin Zhang
- Centre for Nutrition and Food Sciences, ARC Centre of Excellence in Plant Cell Walls, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Brisbane 4072, QLD, Australia
| | - Gina Waltzer
- Centre for Nutrition and Food Sciences, ARC Centre of Excellence in Plant Cell Walls, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Brisbane 4072, QLD, Australia
| | - Michael J Gidley
- Centre for Nutrition and Food Sciences, ARC Centre of Excellence in Plant Cell Walls, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Brisbane 4072, QLD, Australia
| | - Sushil Dhital
- Centre for Nutrition and Food Sciences, ARC Centre of Excellence in Plant Cell Walls, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Brisbane 4072, QLD, Australia.
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6
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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] [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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7
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Senger MR, Gomes LDCA, Ferreira SB, Kaiser CR, Ferreira VF, Silva FP. Kinetics Studies on the Inhibition Mechanism of Pancreatic α-Amylase by Glycoconjugated 1H-1,2,3-Triazoles: A New Class of Inhibitors with Hypoglycemiant Activity. Chembiochem 2012; 13:1584-93. [DOI: 10.1002/cbic.201200272] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Indexed: 11/07/2022]
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8
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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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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9
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Butterworth PJ, Warren FJ, Ellis PR. Human α-amylase and starch digestion: An interesting marriage. STARCH-STARKE 2011. [DOI: 10.1002/star.201000150] [Citation(s) in RCA: 199] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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10
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Zhang G, Hamaker BR. Slowly digestible starch: concept, mechanism, and proposed extended glycemic index. Crit Rev Food Sci Nutr 2010; 49:852-67. [PMID: 19960393 DOI: 10.1080/10408390903372466] [Citation(s) in RCA: 291] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Starch is the major glycemic carbohydrate in foods, and its nutritional property is related to its rate and extent of digestion and absorption in the small intestine. A classification of starch into rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) based on the in vitro Englyst test is used to specify the nutritional quality of starch. Both the RDS and RS fractions have been extensively studied while there are only limited studies on the intermediate starch fraction of SDS, particularly regarding its structural basis and slow digestion mechanism. The current understanding of SDS including its concept, measurement method, structural basis and mechanism, physiological consequences, and approaches to make SDS is reviewed. An in vivo method of extended glycemic index (EGI) is proposed to evaluate its metabolic effect and related health consequences.
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Affiliation(s)
- Genyi Zhang
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu Province, People's Republic of China
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11
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D'Amico S, Sohier JS, Feller G. Kinetics and energetics of ligand binding determined by microcalorimetry: insights into active site mobility in a psychrophilic alpha-amylase. J Mol Biol 2006; 358:1296-304. [PMID: 16580683 DOI: 10.1016/j.jmb.2006.03.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2005] [Revised: 01/31/2006] [Accepted: 03/02/2006] [Indexed: 11/24/2022]
Abstract
A new microcalorimetric method for recording the kinetic parameters k(cat), K(m) and K(i) of alpha-amylases using polysaccharides and oligosaccharides as substrates is described. This method is based on the heat released by glycosidic bond hydrolysis. The method has been developed to study the active site properties of the cold-active alpha-amylase produced by an Antarctic psychrophilic bacterium in comparison with its closest structural homolog from pig pancreas. It is shown that the psychrophilic alpha-amylase is more active on large macromolecular substrates and that the higher rate constants k(cat) are gained at the expense of a lower affinity for the substrate. The active site is able to accommodate larger inhibitory complexes, resulting in a mixed-type inhibition of starch hydrolysis by maltose. A method for recording the binding enthalpies by isothermal titration calorimetry in a low-affinity system has been developed, allowing analysis of the energetics of weak ligand binding using the allosteric activator chloride. It is shown that the low affinity of the psychrophilic alpha-amylase for chloride is entropically driven. The high enthalpic and entropic contributions of activator binding suggest large structural fluctuations between the free and the bound states of the cold-active enzyme. The kinetic and thermodynamic data for the psychrophilic alpha-amylase indicate that the strictly conserved side-chains involved in substrate binding and catalysis possess an improved mobility, responsible for activity in the cold, and resulting from the disappearance of stabilizing interactions far from the active site.
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Affiliation(s)
- S D'Amico
- Laboratory of Biochemistry, University of Liège, Institute of Chemistry B6a, B-4000 Liège-Sart Tilman, Belgium
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12
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Heyl DL, Fernandes S, Khullar L, Stephens J, Blaney E, Opang-Owusu H, Stahelin B, Pasko T, Jacobs J, Bailey D, Brown D, Milletti MC. Correlation of LUMO localization with the α-amylase inhibition constant in a Tendamistat-based series of linear and cyclic peptides. Bioorg Med Chem 2005; 13:4262-8. [PMID: 15927835 DOI: 10.1016/j.bmc.2005.04.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2005] [Revised: 04/08/2005] [Accepted: 04/11/2005] [Indexed: 11/15/2022]
Abstract
The glycosidase alpha-amylase is responsible for the hydrolysis of alpha(1-->4) glycosidic linkages found in dietary starch as one means for controlling blood sugar level. The effect of alpha-amylase is detrimental, however, in the disease state diabetes mellitus, where blood glucose levels are elevated due to a biochemical defect. Inhibition of the enzyme's activity would reduce glucose absorption by the small intestine. Our objective was to develop small peptides based on essential binding elements of the natural protein inhibitor, Tendamistat. These smaller analogs may be better studied structurally and conformationally to help us understand molecular-level interactions. In addition, we have been able to correlate the activity of our compounds with the lowest unoccupied molecular orbital (LUMO) localization in energy-minimized conformations. The positive charge/LUMO of most active inhibitors is localized on the central Arg residue of the required triplet. This provides a predictive model for the design of active molecules.
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Affiliation(s)
- Deborah L Heyl
- Department of Chemistry, Eastern Michigan University, Ypsilanti, MI 48197, USA.
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13
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Honda Y, Kitaoka M, Tokuyasu K, Hayashi K. Reaction Mechanism of Chitinase Belonging to Glycosidase Family 18. J Appl Glycosci (1999) 2004. [DOI: 10.5458/jag.51.155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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14
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Fukamizo T, Sasaki C, Schelp E, Bortone K, Robertus JD. Kinetic properties of chitinase-1 from the fungal pathogen Coccidioides immitis. Biochemistry 2001; 40:2448-54. [PMID: 11327866 DOI: 10.1021/bi001537s] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The endochitinase from Coccidioides immitis (CiX1) is a member of the class 18 chitinase family. Here we show the enzyme functions by a retaining catalytic mechanism; that is, the beta-conformation of the chitin substrate linkages is preserved after hydrolysis. The pattern of cleavage of N-acetyglucosamine (GlcNAc) oligosaccharide substrates has been determined. (GlcNAc)6 is predominantly cleaved into (GlcNAc)2 and (GlcNAc)4, where the (GlcNAc)2 group arises from the nonreducing end of the substrate and is formed as the beta-anomer. With time, transglycosylation occurs, generating (GlcNAc)8 from the product dimer and fresh hexamer. Similar patterns are seen for the cleavage of (GlcNAc)5 and (GlcNAc)4 where dimers cleaved from the nonreducing end reflect the most common binding and hydrolysis pattern. Intrinsic fluorescence measurements suggest the dissociation constant for (GlcNAc)4 is 50 microM. Synthetic substrates with fluorescent leaving groups exhibit complicated profiles in the relationship between initial velocity and substrate concentration, making it difficult to obtain the values of kinetic constants. An improved theoretical analysis of the time-course of (GlcNAc)6 degradation allows the unitary free energy of binding of the individual subsites of the enzyme to be estimated. The free energy values obtained are consistent with the dissociation constant obtained by fluorescence measurements, and generate a model of substrate interaction that can be tested against the crystal structure of the enzyme.
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Affiliation(s)
- T Fukamizo
- Institute of Cellular and Molecular Biology, Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712, USA
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15
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Honda Y, Tanimori S, Kirihata M, Kaneko S, Tokuyasu K, Hashimoto M, Watanabe T, Fukamizo T. Kinetic analysis of the reaction catalyzed by chitinase A1 from Bacillus circulans WL-12 toward the novel substrates, partially N-deacetylated 4-methylumbelliferyl chitobiosides. FEBS Lett 2000; 476:194-7. [PMID: 10913612 DOI: 10.1016/s0014-5793(00)01729-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The kinetic behavior of chitinase A1 from Bacillus circulans WL-12 was investigated using the novel fluorogenic substrates, N-deacetylated 4-methylumbelliferyl chitobiosides [GlcN-GlcNAc-UMB (2), GlcNAc-GlcN-UMB (3), and (GlcN)(2)-UMB (4)], and the results were compared with those obtained using 4-methylumbelliferyl N, N'-diacetylchitobiose [(GlcNAc)(2)-UMB (1)] as the substrate. The chitinase did not release the UMB moiety from compound 4, but successfully released UMB from the other substrates. k(cat)/K(m) values determined from the releasing rate of the UMB moiety were: 145.3 for 1, 8.3 for 2, and 0.1 s(-1) M(-1) for 3. The lack of an N-acetyl group at subsite (-1) reduced the activity to a level 0.1% of that obtained with compound 1, while the absence of the N-acetyl group at subsite (-2) reduced the relative activity to 5.7%. These observations strongly support the theory that chitinase A1 catalysis occurs via a 'substrate-assisted' mechanism. Using these novel fluorogenic substrates, we were able to quantitatively evaluate the recognition specificity of subsite (-2) toward the N-acetyl group of the substrate sugar residue. The (-2) subsite of chitinase A1 was found to specifically recognize an N-acetylated sugar residue, but this specificity was not as strict as that found in subsite (-1).
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Affiliation(s)
- Y Honda
- Laboratory of Bioorganic Chemistry, College of Agriculture, Osaka Prefecture University, Sakai, Osaka, Japan.
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16
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André G, Buléon A, Haser R, Tran V. Amylose chain behavior in an interacting context. III. Complete occupancy of the AMY2 barley alpha-amylase cleft and comparison with biochemical data. Biopolymers 1999; 50:751-62. [PMID: 10547530 DOI: 10.1002/(sici)1097-0282(199912)50:7<751::aid-bip8>3.0.co;2-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In the first two papers of this series, the tools necessary to evaluate substrate ring deformations were developed, and then the modeling of short amylose fragments (maltotriose and maltopentaose) inside the catalytic site of barley alpha-amylase was performed. In this third paper, this docking has been extended to the whole catalytic cleft. A systematic approach to extend the substrate was used on the reducing side from the previous enzyme/pentasaccharide complex. However, due to the lack of an obvious subsite at the nonreducing side, an alternate protocol has been chosen that incorporates biochemical information on the enzyme and features on the substrate shape as well. As a net result, ten subsites have been located consistent with the distribution of Ajandouz et al. (E. H. Ajandouz, J. Abe, B. Svensson, and G. Marchis-Mouren, Biochimica Biophysica Acta, 1992, Vol. 1159, pp. 193-202) and corresponding binding energies were estimated. Among them, two extreme subsites (-6) and (+4), with stacking residues Y104 and Y211, respectively, have strong affinities with glucose rings added to the substrate. No other deformation has been found for the new glucose rings added to the substrate; therefore, only ring A of the DP 10 fragment has a flexible form when interacting with the inner stacking residues Y51. Global conservation of the helical shape of the substrate can be postulated in spite of its significant distortion at subsite (-1).
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Affiliation(s)
- G André
- Laboratoire de Physico-Chimie des Macromolécules, INRA, BP 71627-44316 Nantes Cedex 03, France
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17
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Suganuma T, Maeda Y, Kitahara K, Nagahama T. Study of the action of human salivary alpha-amylase on 2-chloro-4-nitrophenyl alpha-maltotrioside in the presence of potassium thiocyanate. Carbohydr Res 1997; 303:219-27. [PMID: 9352636 DOI: 10.1016/s0008-6215(97)00150-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The degradation mechanism of a synthetic substrate, 2-chloro-4-nitrophenyl alpha-maltotrioside (CNP-G3), by human salivary alpha-amylase (HSA) was investigated by kinetic and product analyses. It was observed that the enzyme attacked the various CNP-maltooligosaccharides (CNP-G3 to CNP-G6) releasing free CNP. Addition of 500 mM potassium thiocyanate (KSCN) was also found to greatly increase the rates of CNP-release. It was the fastest with CNP-G3, and, in the presence of KSCN, was almost comparable to that of degradation of maltopentaose (G5). On the other hand, addition of KSCN decreased the rate of cleavage between glucan-glucan bonds in maltopentaose. Product analysis showed that KSCN addition altered the cleavage distribution which occurred 100% at the bond between CNP and G3, and that product distribution of free CNP was largely dependent on substrate concentration. Formation of CNP-G6, a larger product than the original substrate CNP-G3, was found to be present in the digest at high concentrations of substrate and in the presence of KSCN. Based on these results, a degradation pathway for CNP-G3 involving transglycosylation besides direct hydrolysis is proposed. The increase of the CNP-release by the addition of KSCN would result from a corresponding increase in the interaction between the CNP moiety and the corresponding subsite near the catalytic site, as well as the enhancement of the catalytic efficiency.
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Affiliation(s)
- T Suganuma
- Department of Biochemical Science and Technology, Faculty of Agriculture, Kagoshima University, Japan
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18
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Alkazaz M, Desseaux V, Marchis-Mouren G, Payan F, Forest E, Santimone M. The mechanism of porcine pancreatic alpha-amylase. Kinetic evidence for two additional carbohydrate-binding sites. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 241:787-96. [PMID: 8944767 DOI: 10.1111/j.1432-1033.1996.00787.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Kinetics of inhibition of the two porcine pancreatic alpha-amylase components (PPA I and PPA II) by acarbose were performed using reduced DP18-maltodextrin and amylose as substrates. Similar Line-weaver-Burk primary plots were obtained. Two mixed non-competitive models are proposed. X-ray crystallographic data [Qian, M., Buisson, G., Duée. E., Haser, R. & Payan, F. (1994) Biochemistry 33, 6284-6294] are in support of the mixed non-competitive inhibition model which involves abortive complexes. Secondary plots are different; inhibition of reduced DP18-maltodextrin hydrolysis gives straight-lines plots while amylose gives parabolic curves. These results, confirmed by Dixon-plot analyses, allow us to postulate that, in inhibition of reduced DP18-maltodextrin hydrolysis, one molecule of acarbose is bound/ amylase molecule. In contrast, using amylose as a substrate, two molecules of acarbose are bound. These kinetically determined binding sites might correspond to surface sites found by X-ray crystallography [Qian, M., Haser, R. & Payan, F. (1995) Protein Sci. 4, 747-755]; the glucose site close to the active site and the maltose site, 2 nm away. In conclusion, no significant difference between PPA I and PPA II has been observed, either from molecular mass or from kinetic behaviours; this suggests multiple forms of the enzyme. A general mechanism of PPA action is proposed; in addition to the active site, long-chain substrate hydrolysis requires the glucose-binding site and the maltose-binding site, while only one site is necessary for the hydrolysis of short chain substrate.
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Affiliation(s)
- M Alkazaz
- Laboratoire de Biochimie et Biologie de la Nutrition URA-CNRS 1820, Faculté des Sciences et Techniques de St Jérôme, Université d'Aix-Marseille, France
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19
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Malet C, Vallés J, Bou J, Planas A. A specific chromophoric substrate for activity assays of 1,3-1,4-beta-D-glucan 4-glucanohydrolases. J Biotechnol 1996; 48:209-19. [PMID: 8862000 DOI: 10.1016/0168-1656(96)01511-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The synthesis of 4-methylumbelliferyl 3-beta-O-cellobiosyl-beta-D-glucopyranoside (3a) and its use as specific substrate to monitor enzyme activity of 1,3-1,4-beta-D-glucan 4-glucanohydrolases are described. The chromophoric substrate 3a is prepared by a chemoenzymatic approach starting from barley grain, whose beta-D-glucan polysaccharide is degraded down to a tri- and tetrasaccharide by an extracellular extract of recombinant E. coli expressing and secreting Bacillus licheniformis 1,3-1,4-beta-glucanase. The trisaccharide 1 is further chemically transformed into the title compound. Its use as substrate for an enzyme activity assay, the specificity of cleavage, and kinetic parameters are reported. As it undergoes a single glycosidic bond hydrolysis with release of 4-methylumbelliferone, direct UV monitoring of the reaction provides a sensitive kinetic assay of the enzyme action.
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Affiliation(s)
- C Malet
- Department of Organic Chemistry, CETS Institut Químic de Sarrià, Universitat Ramon Llull, Barcelona, Spain
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20
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Ajandouz EH, Marchis-Mouren GJ. Subsite mapping of porcine pancreatic alpha-amylase I and II using 4-nitrophenyl-alpha-maltooligosaccharides. Carbohydr Res 1995; 268:267-77. [PMID: 7736471 DOI: 10.1016/0008-6215(94)00335-d] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The catalytic efficiency (kcat/Km) and the cleaved bond distribution for the nitrophenylated maltooligosaccharides, p-NPGlcn (2 < or = n < or = 7) hydrolysed by porcine pancreatic alpha-amylase isozymes I and II were determined. The subsite affinities (Ai) were calculated from the p-NPGlcn (4 < or = n < or = 7) hydrolysis data. Five subsites (-3 to 2) bind glucosidic residues with a positive affinity. No additional subsites could be detected both at the reducing end (3, 4, 5) and at the nonreducing end (-4, -5, -6). The energetic profiles of both isozymes are similar. The energetic profile of PPA differs from other alpha-amylases by having both a small number of subsites, and a catalytic subsite with a high positive affinity. Excellent agreement was found between observed catalytic efficiency values and those calculated from the subsite affinities.
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Affiliation(s)
- E H Ajandouz
- Laboratoire de Biochimie et Biologie de la Nutrition, URA-CNRS 1820, Université d'Aix-Marseille III, Faculté des Sciences, France
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21
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Oosthuizen V, Naudé RJ, Oelofsen W, Koji M, Hisao K. Ostrich pancreatic α-amylase: Kinetic properties, amino terminal sequence and subsite structure. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/0020-711x(94)90101-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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22
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Heymann H, Günther S. Calculation of subsite affinities of human small intestinal glucoamylase-maltase. BIOLOGICAL CHEMISTRY HOPPE-SEYLER 1994; 375:451-5. [PMID: 7945994 DOI: 10.1515/bchm3.1994.375.7.451] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Several years ago, Hiromi et al. (1973) Biochim. Biophys. Acta 302, 362-375 proposed a theory for the action patterns of glucoamylases, based on data from steady-state kinetics. The Michaelis-Menten constants (Km) and the turnover number for maltooligosaccharides were used to evaluate the subsite affinities. We have now used this method for evaluating the subsite affinities for glucoamylases(EC 3.2.1.3)-maltase (EC 3.2.1.20) from human intestinal mucosa. For calculation of the subsite affinities, A1 and A2, and the intrinsic rate constant kint, we use a modified algorithm and a computer program for nonlinear least square fitting. Considerable substrate inhibition was shown by maltotriose, minor inhibition by maltotetraose, and no inhibition by maltose and the other maltooligosaccharides. This indicates a more complex kinetic behaviour of the enzyme with respect to maltotriose. Evaluation of the subsites reveals that A2 is the main binding site (18.1 kJ/mol), whereas the other affinities, with the exception of A1, are lower than 2.5 kJ/mol.
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Affiliation(s)
- H Heymann
- Medizinische Hochschule Hannover, Zentrum Biochemie, Arbeitsbereich Enzymologie, Germany
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23
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Lehmann J, Schmidt-Schuchardt M. Spacer-modified oligosaccharides as photoaffinity probes for porcine pancreatic alpha-amylase. Methods Enzymol 1994; 247:265-88. [PMID: 7898358 DOI: 10.1016/s0076-6879(94)47021-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- J Lehmann
- Albert-Ludwigs-Universität Freiburg, Institute für Organische Chemie und Biochemie, Germany
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24
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25
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Ajandouz EH, Abe J, Svensson B, Marchis-Mouren G. Barley malt-alpha-amylase. Purification, action pattern, and subsite mapping of isozyme 1 and two members of the isozyme 2 subfamily using p-nitrophenylated maltooligosaccharide substrates. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1159:193-202. [PMID: 1390923 DOI: 10.1016/0167-4838(92)90025-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Isoforms AMY1, AMY2-1 and AMY2-2 of barley alpha-amylase were purified from malt. AMY2-1 and AMY2-2 are both susceptible to barley alpha-amylase/subtilisin inhibitor. The action of these isoforms is compared using substrates ranging from p-nitrophenylmaltoside through p-nitrophenylmaltoheptaoside. The kcat/Km values are calculated from the substrate consumption. The relative cleavage frequency of different substrate bonds is given by the product distribution. AMY2-1 is 3-8-fold more active than AMY1 toward p-nitrophenylmaltotrioside through p-nitrophenylmaltopentaoside. AMY2-2 is 10-50% more active than AMY2-1. The individual subsite affinities are obtained from these data. The resulting subsite maps of the isoforms are quite similar. They comprise four and six glucosyl-binding subsites towards the reducing and the non-reducing end, respectively. Towards the non-reducing end, the sixth and second subsites have a high affinity, the third has very low or even lack of affinity and the first (catalytic subsite) has a large negative affinity. The affinity declines from moderate to low for subsites 1 through 4 toward the reducing end. AMY1 has clearly a more negative affinity at the catalytic subsite, but larger affinities at both the fourth subsites, compared to AMY2. AMY2-1 has lower affinity than AMY2-2 at subsites adjacent to the catalytic site, and otherwise mostly higher affinities than AMY2-2. Theoretical kcat/Km values show excellent agreement with experimental values.
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Affiliation(s)
- E H Ajandouz
- BBMN Faculté des Sciences, Université d'Aix-Marseille III, France
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26
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Leloup VM, Colonna P, Marchis-Mouren G. Mechanism of the adsorption of pancreatic alpha-amylase onto starch crystallites. Carbohydr Res 1992; 232:367-74. [PMID: 1423363 DOI: 10.1016/0008-6215(92)80069-d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- V M Leloup
- Institut National de la Recherche Agronomique, Nantes, France
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27
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Desseaux V, Payan F, Ajandouz EH, Svensson B, Haser R, Marchis-Mouren G. Effect of limited proteolysis in the 8th loop of the barrel and of antibodies on porcine pancreas amylase activity. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1080:237-44. [PMID: 1720021 DOI: 10.1016/0167-4838(91)90008-n] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The porcine pancreatic alpha-amylase is a (beta/alpha)8-barrel protein, containing domains A and B (peptide sequence 1-403) and a distinct C-domain (peptide sequence 404-496). Separation of the terminal C-domain from the A and B domains has been attempted by limited proteolysis in the hinge region. Subtilisin was found to hydrolyse amylase between residues 369 and 370 situated in the loop between the eighth beta-strand and alpha-helix. The cleaved amylase was isolated by chromatofocusing and found to retain about 60% of the activity of the native enzyme, while the isolated fragments were inactive. Antigen binding fragments prepared from polyclonal antibodies to native amylase and the CNBr-fragment P1 (peptide sequence 395-496) respectively, were tested for influence on the enzyme activity. Antibodies directed against P1 had no effect whereas antibodies against the peptide sequence 1-394 and amylase respectively inhibited hydrolysis of substrates having four or more glucose residues but not of shorter oligomaltosides. Crystallographic analysis revealed that changes in the region of residue 369 might affect the conformation of the active site as well as of a second binding site. This site, located on the enzyme surface, is proposed to be required for the hydrolysis of larger substrates.
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Affiliation(s)
- V Desseaux
- BBMN Faculté des Sciences, Université d'Aix-Marseille III, France
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28
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Rubbo H, Radi R, Prodanov E. Substrate inhibition of xanthine oxidase and its influence on superoxide radical production. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1074:386-91. [PMID: 1653611 DOI: 10.1016/0304-4165(91)90089-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The influence of substrate inhibition on xanthine oxidase-intramolecular electron transport was studied by steady-state kinetic analysis. Experiments with hypoxanthine and xanthine up to 900 microM indicated an inhibition pattern which fitted an equation of the general form nu 0 = nu max . [S]/(Km + a[S] + b[S]2/Ki). Univalent electron flux to oxygen was favored at substrate concentrations above 50 microM. This augmentation of univalent flux percentage that appeared at a high substrate concentration was greater for hypoxanthine that xanthine and at pH 8.3 than at 9.5. Our results support a mechanism of inhibition in which a substrate-reduced enzyme, non-productive Michaelis complex was formed. It is possible that this non-productive complex favored the univalent pathway of enzyme reoxidation (superoxide production) by increasing the midpoint redox potential of the molybdenum active site.
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Affiliation(s)
- H Rubbo
- Department of Biochemistry, Faculty of Medicine, University of the Republic, Montevideo, Uruguay
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29
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Desseaux V, Seigner C, Pierron Y, Grisoni ML, Marchis-Mouren G. Porcine pancreatic alpha-amylase: a model for structure--function studies of homodepolymerases. Biochimie 1988; 70:1163-70. [PMID: 3147708 DOI: 10.1016/0300-9084(88)90181-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The amino acid sequence of the porcine pancreatic alpha-amylase chain (496 residues) contains four regions (96-101, 193-201, 233-236 and 295-300) which are highly homologous in amylases of different origins. These regions all belong to the N-terminal domain of the enzyme. Limited proteolysis by subtilisin allows a cut to be made at bond 369-370. Purified fragments indicate that both N- and C-terminal domains are required for amylolytic activity. Kinetic studies and reaction product analysis using oligomaltosides, their nitrophenylated derivatives and amylose as the substrate allowed us to establish: 1) the energy profile of the 5 subsites and, especially, that subsite number 3 is catalytic; 2) that 2 molecules of either maltotriose or its o-nitrophenylated analog or maltose bind to the active site at high substrate concentration. Such a subsite occupancy was confirmed by fluorescence quenching studies. Finally the hydrolysis of p-nitrophenylmaltoside was studied as a function of pH. In contrast to starch hydrolysis, the initial velocity plots for nitrophenol and p-nitrophenylglucoside liberation both gave a narrow pH-activity peak with a maximum value around pH 5.5. All data provide strong evidence for the participation of 2 carboxylic residues in the catalysis.
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Affiliation(s)
- V Desseaux
- Institut de Chimie Biologique, Université d'Aix-Marseille, France
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30
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Nakatani H. Selective inhibition of histidine-modified pancreatic alpha-amylase by proteinaceous inhibitor from Phaseolus vulgaris. Arch Biochem Biophys 1988; 263:364-8. [PMID: 3259857 DOI: 10.1016/0003-9861(88)90647-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Chemical modification of two histidine residues of porcine pancreatic alpha-amylase (EC 3.2.1.1) by diethyl pyrocarbonate in the presence of a high concentration of maltotriose caused a decrease of amylase activity and an increase of maltosidase activity (hydrolysis of p-nitrophenyl-alpha-maltoside). By binding a proteinaceous inhibitor from Phaseolus vulgaris (white kidney bean) with the modified enzyme, the amylase activity was further decreased but the maltosidase activity was retained to about 100% that of the native enzyme. Both amylase and maltosidase activities of the native enzyme were almost completely inhibited by the proteinaceous inhibitor. The increase of maltosidase activity by histidine modification was due to an increase of kcat, whereas the Km value was not changed; but binding of the proteinous inhibitor affected mainly the Km value of the modified enzyme.
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Affiliation(s)
- H Nakatani
- Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, Japan
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31
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32
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Seigner C, Prodanov E, Marchis-Mouren G. The determination of subsite binding energies of porcine pancreatic alpha-amylase by comparing hydrolytic activity towards substrates. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 913:200-9. [PMID: 3496119 DOI: 10.1016/0167-4838(87)90331-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The active centre of porcine pancreatic alpha-amylase contains five subsites. Their occupancy has been studied using as a substrate maltooligosaccharide of various chain lengths (maltose up to maltoheptaose), some of their p- and o-nitrophenylated derivatives, and 412-residue amylose. Quantitative analysis of the digestion products allowed the determination of the subsite occupancy for the various productive complexes, the bond cleavage frequency and respective kcati (where i is the binding mode). The catalytic efficiency (kcat/Km) increases with chain length from maltose (2 M-1 X S-1) up to amylose (1.06 X 10(7) M-1 X S-1). The kinetic parameters of p-nitrophenylmaltoside hydrolysis are quite close to those of maltose, and the ortho compound behaves as maltotriose. Determination of binding energy of glucose residue at the various subsites calculated according to the method of Hiromi et al. (Hiromi, K., Nitta, Y., Numata, C. and Ono, S. (1973) Biochim. Biophys. Acta 302, 362-375) did not give consistent results. A method is proposed based on certain properties of porcine pancreatic alpha-amylase, especially the non-interaction of the p-nitrophenyl moiety of the maltose derivative with subsites 1 and 2, and the o-nitrophenyl group which interacts in a similar way to a glucose residue at the reducing end, and on the grounds that the amylase-amylose complexes are of the productive type. In addition, binding energy differences were calculated from substrates with the same chain length. The subsite energy profile is characterized by a low value at subsite 3 which confirms this subsite as the catalytic one. Another consequence is that the hydrolysis rate constant of productive complexes (kintn) (where n is the number of glucose or glucose equivalent residues for a given substrate) varies with chain length which is in conflict with the hypothesis of Hiromi et al.
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33
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Chemical modification of barley malt α-amylase 2: Involvement of tryptophan and tyrosine residues in enzyme activity. ACTA ACUST UNITED AC 1986. [DOI: 10.1007/bf02907163] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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