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Scholtysek L, Poetsch A, Hofmann E, Hemschemeier A. The activation of Chlamydomonas reinhardtii alpha amylase 2 by glutamine requires its N-terminal aspartate kinase-chorismate mutase-tyrA (ACT) domain. PLANT DIRECT 2024; 8:e609. [PMID: 38911017 PMCID: PMC11190351 DOI: 10.1002/pld3.609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 05/08/2024] [Accepted: 05/16/2024] [Indexed: 06/25/2024]
Abstract
The coordination of assimilation pathways for all the elements that make up cellular components is a vital task for every organism. Integrating the assimilation and use of carbon (C) and nitrogen (N) is of particular importance because of the high cellular abundance of these elements. Starch is one of the most important storage polymers of photosynthetic organisms, and a complex regulatory network ensures that biosynthesis and degradation of starch are coordinated with photosynthetic activity and growth. Here, we analyzed three starch metabolism enzymes of Chlamydomonas reinhardtii that we captured by a cyclic guanosine monophosphate (cGMP) affinity chromatography approach, namely, soluble starch synthase STA3, starch-branching enzyme SBE1, and α-amylase AMA2. While none of the recombinant enzymes was directly affected by the presence of cGMP or other nucleotides, suggesting an indirect binding to cGMP, AMA2 activity was stimulated in the presence of L-glutamine (Gln). This activating effect required the enzyme's N-terminal aspartate kinase-chorismate mutase-tyrA domain. Gln is the first N assimilation product and not only a central compound for the biosynthesis of N-containing molecules but also a recognized signaling molecule for the N status. Our observation suggests that AMA2 might be a means to coordinate N and C metabolism at the enzymatic level, increasing the liberation of C skeletons from starch when high Gln levels signal an abundance of assimilated N.
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Affiliation(s)
- Lisa Scholtysek
- Faculty of Biology and Biotechnology, PhotobiotechnologyRuhr University BochumBochumGermany
| | - Ansgar Poetsch
- Faculty of Biology and Biotechnology, Department for Plant BiochemistryRuhr University BochumBochumGermany
- School of Basic Medical SciencesNanchang UniversityNanchangChina
| | - Eckhard Hofmann
- Faculty of Biology and Biotechnology, Protein CrystallographyRuhr University BochumBochumGermany
| | - Anja Hemschemeier
- Faculty of Biology and Biotechnology, PhotobiotechnologyRuhr University BochumBochumGermany
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2
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Williams AE, Gittis AG, Botello K, Cruz P, Martin-Martin I, Valenzuela Leon PC, Sumner B, Bonilla B, Calvo E. Structural and functional comparisons of salivary α-glucosidases from the mosquito vectors Aedes aegypti, Anopheles gambiae, and Culex quinquefasciatus. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2024; 167:104097. [PMID: 38428508 PMCID: PMC10955559 DOI: 10.1016/j.ibmb.2024.104097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/26/2024] [Accepted: 02/26/2024] [Indexed: 03/03/2024]
Abstract
Mosquito vectors of medical importance both blood and sugar feed, and their saliva contains bioactive molecules that aid in both processes. Although it has been shown that the salivary glands of several mosquito species exhibit α-glucosidase activities, the specific enzymes responsible for sugar digestion remain understudied. We therefore expressed and purified three recombinant salivary α-glucosidases from the mosquito vectors Aedes aegypti, Anopheles gambiae, and Culex quinquefasciatus and compared their functions and structures. We found that all three enzymes were expressed in the salivary glands of their respective vectors and were secreted into the saliva. The proteins, as well as mosquito salivary gland extracts, exhibited α-glucosidase activity, and the recombinant enzymes displayed preference for sucrose compared to p-nitrophenyl-α-D-glucopyranoside. Finally, we solved the crystal structure of the Ae. aegypti α-glucosidase bound to two calcium ions at a 2.3 Ångstrom resolution. Molecular docking suggested that the Ae. aegypti α-glucosidase preferred di- or polysaccharides compared to monosaccharides, consistent with enzymatic activity assays. Comparing structural models between the three species revealed a high degree of similarity, suggesting similar functional properties. We conclude that the α-glucosidases studied herein are important enzymes for sugar digestion in three mosquito species.
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Affiliation(s)
- Adeline E Williams
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Apostolos G Gittis
- Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Karina Botello
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Phillip Cruz
- Office of Cyber Infrastructure and Computational Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Ines Martin-Martin
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Paola Carolina Valenzuela Leon
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Benjamin Sumner
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Brian Bonilla
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Eric Calvo
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA.
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3
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Phetlum S, Champasri C. Purification and characterization of amylases from three freshwater fish species providing new insight application as enzyme molecular markers for zymography. FISH PHYSIOLOGY AND BIOCHEMISTRY 2023; 49:1257-1276. [PMID: 37889390 DOI: 10.1007/s10695-023-01255-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 10/12/2023] [Indexed: 10/28/2023]
Abstract
Purification of amylases from digestive tracts of three freshwater fish species with Q-Sepharose Fast Flow and Sephacryl S-200 columns displayed two isoforms of amylases from Osteochilus hasselti (O1, O2) and three isoforms of those from both Hampala dispar (UB, H1, H2) and Puntioplites proctozystron (P1, P2, P3). The optimum pH values displayed at 7.0 and 8.0, while the optimum temperatures revealed at 40 and 50 °C. Almost isoenzyme activities were activated by NaCl and CaCl2, whereas EDTA and SDS strongly inhibited all enzymatic activities. Verification with an atomic absorption spectrophotometry exhibited the presence of Ca2+ ions in the range of 0.02-13.53 ppm per mg protein indicating that amylases are Ca2+ dependent. Molecular weight analysis revealed 12 to 147 kDa. The UB, O1, and H2 amylases with appropriate molecular masses of 64, 49, and 25 kDa validated with LC-MS/MS were selected. Three certain enzymes revealed high stability in a sample buffer after five cycles of freeze-thawing process upon storage at - 20 °C for 12 weeks. No protein degradation was observed on polyacrylamide gel, and the enzymes still displayed sharp and clear bands on zymograms. The result suggested that the purified fish amylases, which expressed high activities and stabilities, were potentially used as enzyme molecular weight markers for zymography.
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Affiliation(s)
- Suthathip Phetlum
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Chamaiporn Champasri
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand.
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Laureys D, Baillière J, Vermeir P, Vanderputten D, De Clippeleer J. The Impact of 10 Unmalted Alternative Adjuncts on Wort Characteristics. Foods 2023; 12:4206. [PMID: 38231655 DOI: 10.3390/foods12234206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/16/2023] [Accepted: 11/20/2023] [Indexed: 01/19/2024] Open
Abstract
Consumers are more than ever in search of novel and exciting beer choices, and brewers are, therefore, continuously experimenting to adapt their product portfolio. One interesting way to naturally incorporate novel flavors and tastes is by using alternative adjuncts, but this is not always an easy and straightforward process. In this study, a 40% unmalted alternative adjunct (einkorn, emmer, spelt, khorasan, quinoa, amaranth, buckwheat, sorghum, teff, and tritordeum) or reference (barley malt, unmalted barley, and unmalted wheat) was added to 60% barley malt, after which three different laboratory mashing processes (Congress mash, Congress mash with pre-gelatinization of the adjunct, and Evans mash) were performed, and their behavior during mashing and the resulting wort characteristics were investigated in detail. Overall, the extraction process of all 10 unmalted alternative adjuncts was not complete for all three laboratory mashing processes, whereby Congress mashing resulted in the highest extract and fastest filtration, whereas Evans mashing resulted in the lowest extract and slowest filtration. Pre-gelatinization of the unmalted was generally only beneficial for adjuncts with high onset starch gelatinization temperatures. This process also inactivated endogenous enzymes in the unmalted adjuncts, which had an adverse effect on the mashing process.
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Affiliation(s)
- David Laureys
- Innovation Centre for Brewing & Fermentation (IBF), Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, 9000 Ghent, Belgium
| | - Jeroen Baillière
- Innovation Centre for Brewing & Fermentation (IBF), Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, 9000 Ghent, Belgium
| | - Pieter Vermeir
- Laboratory of Chemical Analysis (LCA), Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, 9000 Ghent, Belgium
| | - Dana Vanderputten
- Innovation Centre for Brewing & Fermentation (IBF), AgroFoodNature, HOGENT University of Applied Sciences and Arts, Valentin Vaerwyckweg 1, 9000 Ghent, Belgium
| | - Jessika De Clippeleer
- Innovation Centre for Brewing & Fermentation (IBF), Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, 9000 Ghent, Belgium
- Innovation Centre for Brewing & Fermentation (IBF), AgroFoodNature, HOGENT University of Applied Sciences and Arts, Valentin Vaerwyckweg 1, 9000 Ghent, Belgium
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De Schepper C, Gielens D, Courtin C. A new method to isolate and separate small and large starch granules from barley and malt. Food Hydrocoll 2021. [DOI: 10.1016/j.foodhyd.2021.106907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Gupta S, Thokchom SD, Kapoor R. Arbuscular Mycorrhiza Improves Photosynthesis and Restores Alteration in Sugar Metabolism in Triticum aestivum L. Grown in Arsenic Contaminated Soil. FRONTIERS IN PLANT SCIENCE 2021; 12:640379. [PMID: 33777073 PMCID: PMC7991624 DOI: 10.3389/fpls.2021.640379] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 02/11/2021] [Indexed: 05/05/2023]
Abstract
Contamination of agricultural soil by arsenic (As) is a serious menace to environmental safety and global food security. Symbiotic plant-microbe interaction, such as arbuscular mycorrhiza (AM), is a promising approach to minimize hazards of As contamination in agricultural soil. Even though the potential of AM fungi (AMF) in redeeming As tolerance and improving growth is well recognized, the detailed metabolic and physiological mechanisms behind such beneficial effects are far from being completely unraveled. The present study investigated the ability of an AM fungus, Rhizophagus intraradices, in mitigating As-mediated negative effects on photosynthesis and sugar metabolism in wheat (Triticum aestivum) subjected to three levels of As, viz., 0, 25, and 50 mg As kg-1 of soil, supplied as sodium arsenate. As exposure caused significant decrease in photosynthetic pigments, Hill reaction activity, and gas exchange parameters such as net photosynthetic rate, stomatal conductance, transpiration rate, and intercellular CO2 concentration. In addition, As exposure also altered the activities of starch-hydrolyzing, sucrose-synthesizing, and sucrose-degrading enzymes in leaves. Colonization by R. intraradices not only promoted plant growth but also restored As-mediated impairments in plant physiology. The symbiosis augmented the concentration of photosynthetic pigments, enhanced Hill reaction activity, and improved leaf gas exchange parameters and water use efficiency of T. aestivum even at high dose of 50 mg As kg-1 of soil. Furthermore, inoculation with R. intraradices also restored As-mediated alteration in sugar metabolism by modulating the activities of starch phosphorylase, α-amylase, β-amylase, acid invertase, sucrose synthase, and sucrose-phosphate synthase in leaves. This ensured improved sugar and starch levels in mycorrhizal plants. Overall, the study advocates the potential of R. intraradices in bio-amelioration of As-induced physiological disturbances in wheat plant.
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Affiliation(s)
| | | | - Rupam Kapoor
- Department of Botany, University of Delhi, New Delhi, India
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Starch hydrolysis during mashing: A study of the activity and thermal inactivation kinetics of barley malt α-amylase and β-amylase. Carbohydr Polym 2021; 255:117494. [PMID: 33436252 DOI: 10.1016/j.carbpol.2020.117494] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/12/2020] [Accepted: 12/07/2020] [Indexed: 11/20/2022]
Abstract
Hydrolysis of starch is key in several industrial processes, including brewing. Here, the activity and inactivation kinetics of amylases throughout barley malt mashing are investigated, as a prerequisite for rational optimisation of this process. Varietal differences were observed in the activity of α- and β-amylases as a function of temperature for six barley and malt varieties. These differences were not reflected in the resulting wort composition after mashing, using three isothermal phases of 30 min at 45 °C, 62 °C and 72 °C with intermediate heating by 1 °C/min. Thermal inactivation kinetics parameters determined for α- and β-amylases of an industrially relevant malt variety in a diluted system showed that enzymes were inactivated at lower temperatures than expected. The obtained kinetic parameters could predict α-amylase, but not β-amylase inactivation in real mashing conditions, suggesting that β-amylase stability is enhanced during mashing by components present or formed in the mash.
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Zhou L, Li C, White JF, Johnson RD. Synergism between calcium nitrate applications and fungal endophytes to increase sugar concentration in Festuca sinensis under cold stress. PeerJ 2021; 9:e10568. [PMID: 35070512 PMCID: PMC8759379 DOI: 10.7717/peerj.10568] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 11/23/2020] [Indexed: 11/20/2022] Open
Abstract
Epichloë endophytes have been shown to increase tolerance to biotic and abiotic stresses in many cool-season grasses. We investigated the impact of endophyte infection of Festuca sinensis, on root metabolic activity, photosynthetic pigments, leaf relative water content (RWC) and soluble carbohydrates in a field experiment carried out during chilling and irrigation with Ca(NO3)2. A highly significant (P < 0.001) correlation for Epichloë endophytes was observed for root metabolic activity. Ca(NO3)2 affected very significantly root metabolic activity and total chlorophyll (P < 0.001). Low temperature led to highly significant (P < 0.001) reductions in root metabolic activity, RWC, total chlorophyll, chlorophyll a/b ratio, and carotenoid contents. In addition, the fructose concentrations of shoots were greater on the 14th day than on the 28th day and before treatment, whilst the glucose concentration of roots was much higher on the 28th day than before and after 14 days treatment. Moreover, our results indicated that the addition of calcium nitrate contributed to higher levels of total chlorophylls, soluble sugars, sucrose, fructose or glucose in the shoots and roots in both E+ and E- plants during long periods of chilling. These results suggest that Epichloë endophyte infection and/or exogenous calcium nitrate can confer better tolerance to cold stress.
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Affiliation(s)
- Lianyu Zhou
- State Key Laboratory of Grassland Agro-ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry, Ministry of Education; Gansu Tech Innovation Centre, Lanzhou University, Lanzhou, Gansu, China
- Key Laboratory of Medicinal Plant and Animal Resources of the Qinghai-Tibetan Plateau, School of Life Science, Qinghai Normal University, Xining, Qinghai, China
| | - Chunjie Li
- State Key Laboratory of Grassland Agro-ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry, Ministry of Education; Gansu Tech Innovation Centre, Lanzhou University, Lanzhou, Gansu, China
| | - James F. White
- Department of Plant Biology, Rutgers University, New Brunswick, NJ, United States of America
| | - Richard D. Johnson
- Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand
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Yamaguchi T, Yamakawa H, Nakata M, Kuroda M, Hakata M. Suppression of phospholipase D genes improves chalky grain production by high temperature during the grain-filling stage in rice. Biosci Biotechnol Biochem 2019; 83:1102-1110. [DOI: 10.1080/09168451.2019.1580137] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
ABSTRACT
High temperature (HT) during the grain developing stage causes deleterious effects on rice quality resulting in mature grains with a chalky appearance. Phospholipase D (PLD) plays an important role in plants, including responses to environmental stresses. OsPLDα1, α3 and β2-knockdown (KD) plants showed decreased production of chalky grains at HT. HT ripening increased H2O2 accumulated in the developing grains. However, the increase was canceled by the knockdown of OsPLDβ2. Expression levels of OsCATA which is one of three rice catalase genes, in developing grains of OsPLDβ2-KD plants at 10 DAF were increased compared with that in vector-controls in HT growth conditions. Overexpression of OsCATA markedly suppressed the production of chalky grains in HT growth conditions. These results suggested that OsPLDβ2 functions as a negative regulator of the induction of OsCATA and is involved in the production of chalky grains in HT growth conditions.
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Affiliation(s)
| | | | - Masaru Nakata
- Central Region Agricultural Research Center, NARO, Joetsu, Japan
| | - Masaharu Kuroda
- Central Region Agricultural Research Center, NARO, Joetsu, Japan
| | - Makoto Hakata
- Central Region Agricultural Research Center, NARO, Joetsu, Japan
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Liao SM, Liang G, Zhu J, Lu B, Peng LX, Wang QY, Wei YT, Zhou GP, Huang RB. Influence of Calcium Ions on the Thermal Characteristics of α-amylase from Thermophilic Anoxybacillus sp. GXS-BL. Protein Pept Lett 2019; 26:148-157. [PMID: 30652633 PMCID: PMC6416487 DOI: 10.2174/0929866526666190116162958] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/07/2019] [Accepted: 01/08/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND α-Amylases are starch-degrading enzymes and used widely, the study on thermostability of α-amylase is a central requirement for its application in life science and biotechnology. OBJECTIVE In this article, our motivation is to study how the effect of Ca2+ ions on the structure and thermal characterization of α-amylase (AGXA) from thermophilic Anoxybacillus sp.GXS-BL. METHODS α-Amylase activity was assayed with soluble starch as the substrate, and the amount of sugar released was determined by DNS method. For AGXA with calcium ions and without calcium ions, optimum temperature (Topt), half-inactivation temperature (T50) and thermal inactivation (halflife, t1/2) was evaluated. The thermal denaturation of the enzymes was determined by DSC and CD methods. 3D structure of AGXA was homology modeled with α-amylase (5A2A) as the template. RESULTS With calcium ions, the values of Topt, T50, t1/2, Tm and ΔH in AGXA were significantly higher than those of AGXA without calcium ions, showing calcium ions had stabilizing effects on α-amylase structure with the increased temperature. Based on DSC measurements AGXA underwent thermal denaturation by adopting two-state irreversible unfolding processes. Based on the CD spectra, AGXA without calcium ions exhibited two transition states upon unfolding, including α- helical contents increasing, and the transition from α-helices to β-sheet structures, which was obviously different in AGXA with Ca2+ ions, and up to 4 Ca2+ ions were located on the inter-domain or intra-domain regions according to the modeling structure. CONCLUSION These results reveal that Ca2+ ions have pronounced influences on the thermostability of AGXA structure.
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Affiliation(s)
| | | | | | | | | | | | | | - Guo-Ping Zhou
- Address correspondence to these authors at the Department of Bioengineering, College of Life Science and Technology, Guangxi University, Nanning, 530004, China; E-mail: , Gordon Life Science Institute, 53 South Cottage Road Belmont, MA, 02478, USA; Tel/Fax: +1-9199875774/ +1-9195215550; E-mail:
| | - Ri-Bo Huang
- Address correspondence to these authors at the Department of Bioengineering, College of Life Science and Technology, Guangxi University, Nanning, 530004, China; E-mail: , Gordon Life Science Institute, 53 South Cottage Road Belmont, MA, 02478, USA; Tel/Fax: +1-9199875774/ +1-9195215550; E-mail:
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Almulaiky YQ, Aqlan FM, Aldhahri M, Baeshen M, Khan TJ, Khan KA, Afifi M, AL-Farga A, Warsi MK, Alkhaled M, Alayafi AAM. α-Amylase immobilization on amidoximated acrylic microfibres activated by cyanuric chloride. ROYAL SOCIETY OPEN SCIENCE 2018; 5:172164. [PMID: 30564380 PMCID: PMC6281920 DOI: 10.1098/rsos.172164] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 11/02/2018] [Indexed: 02/05/2023]
Abstract
Enzyme immobilization is one of the most important techniques for industrial applications. It makes the immobilized enzyme more stable and advantageous than the free form in different aspects. α-Amylase was immobilized on 4% cyanuric chloride-activated amidoximated acrylic fabric at pH 7.0 with (79%) maximum efficiency. A field emission scanning electron microscope and Fourier transform infrared were used to confirm the immobilization process. Even after being recycled 10 times, the immobilized enzyme lost just 28% of its initial activity. Owing to immobilization, the pH of the soluble α-amylase was shifted from 6.0 to 6.5. The immobilized α-amylases showed thermal stability at 60°C, and became more resistant to heavy metal ions. The k m values of the immobilized and soluble α-amylases were 9.6 and 3.8 mg starch ml-1, respectively. In conclusion, this method shows that the immobilized α-amylase proved to be more efficient than its soluble form, and hence could be used during saccharification of starch.
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Affiliation(s)
- Yaaser Q. Almulaiky
- Department of Biochemistry, Faculty of Science, University of Jeddah, Jeddah, Saudi Arabia
- Chemistry Department, Faculty of Applied Science, Taiz University, Taiz, Yemen
- Author for correspondence: Yaaser Q. Almulaiky e-mail:
| | - Faisal M. Aqlan
- Chemistry Department, Faculty of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Musab Aldhahri
- Department of Biochemistry, Faculty of Science, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
- Center of Nanotechnology, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohammed Baeshen
- Department of Biology, Faculty of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Tariq Jamal Khan
- Stem Cell P2 Laboratory, The Center for Reproductive Medicine, Shantou University Medical College, Shantou 515041, People's Republic of China
| | - Khalid A. Khan
- Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohamed Afifi
- Department of Biology, Faculty of Science, University of Jeddah, Jeddah, Saudi Arabia
- Biochemistry Department, Faculty of Veterinary Medicine, Zagazig University, Egypt
| | - Ammar AL-Farga
- Department of Biochemistry, Faculty of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Mohiuddin Khan Warsi
- Department of Biochemistry, Faculty of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Mohammed Alkhaled
- Department of Biology, Faculty of Science, University of Jeddah, Jeddah, Saudi Arabia
| | - Aisha A. M. Alayafi
- Department of Biology, Faculty of Science, University of Jeddah, Jeddah, Saudi Arabia
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Evans DE, Collins H, Eglinton J, Wilhelmson A. Assessing the Impact of the Level of Diastatic Power Enzymes and Their Thermostability on the Hydrolysis of Starch during Wort Production to Predict Malt Fermentability. JOURNAL OF THE AMERICAN SOCIETY OF BREWING CHEMISTS 2018. [DOI: 10.1094/asbcj-63-0185] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- D. Evan Evans
- Tasmanian Institute of Agricultural Research (TIAR), University of Tasmania, Private Bag 54, Hobart, Tas 7001, Australia
| | - Helen Collins
- School of Agriculture and Wine, Waite Campus, University of Adelaide, Glen Osmond, SA 5064, Australia
| | - Jason Eglinton
- School of Agriculture and Wine, Waite Campus, University of Adelaide, Glen Osmond, SA 5064, Australia
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Ma Z, Bykova NV, Igamberdiev AU. Cell signaling mechanisms and metabolic regulation of germination and dormancy in barley seeds. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.cj.2017.08.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Singh K, Ahmad F, Singh VK, Kayastha K, Kayastha AM. Purification, biochemical characterization and Insilico modeling of α-amylase from Vicia faba. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.03.058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Pompeiano A, Damiani CR, Stefanini S, Vernieri P, Huarancca Reyes T, Volterrani M, Guglielminetti L. Seedling Establishment of Tall Fescue Exposed to Long-Term Starvation Stress. PLoS One 2016; 11:e0166131. [PMID: 27832166 PMCID: PMC5104456 DOI: 10.1371/journal.pone.0166131] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 10/24/2016] [Indexed: 11/21/2022] Open
Abstract
In germinating seeds under unfavorable environmental conditions, the mobilization of stores in the cotyledons is delayed, which may result in a different modulation of carbohydrates balance and a decrease in seedling vigor. Tall fescue (Festuca arundinacea Schreb.) caryopses grown at 4°C in the dark for an extended period in complete absence of nutrients, showed an unexpected ability to survive. Seedlings grown at 4°C for 210 days were morphologically identical to seedlings grown at 23°C for 21 days. After 400 days, seedlings grown at 4°C were able to differentiate plastids to chloroplast in just few days once transferred to the light and 23°C. Tall fescue exposed to prolonged period at 4°C showed marked anatomical changes: cell wall thickening, undifferentiated plastids, more root hairs and less xylem lignification. Physiological modifications were also observed, in particular related to sugar content, GA and ABA levels and amylolytic enzymes pattern. The phytohormones profiles exhibited at 4 and 23°C were comparable when normalized to the respective physiological states. Both the onset and the completion of germination were linked to GA and ABA levels, as well as to the ratio between these two hormones. All plants showed a sharp decline in carbohydrate content, with a consequent onset of gradual sugar starvation. This explained the slowed then full arrest in growth under both treatment regimes. The analysis of amylolytic activity showed that Ca2+ played a central role in the stabilization of several isoforms. Overall, convergence of starvation and hormone signals meet in crosstalk to regulate germination, growth and development in tall fescue.
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Affiliation(s)
- Antonio Pompeiano
- Laboratory of Ecological Plant Physiology, Global Change Research Institute CAS, Brno, Czech Republic
| | | | - Sara Stefanini
- Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy
| | - Paolo Vernieri
- Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy
| | | | - Marco Volterrani
- Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy
| | - Lorenzo Guglielminetti
- Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy
- * E-mail:
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Wang Y, Kuramitsu Y, Baron B, Kitagawa T, Akada J, Tokuda K, Cui D, Nakamura K. PERK/CHOP contributes to the CGK733-induced vesicular calcium sequestration which is accompanied by non-apoptotic cell death. Oncotarget 2016; 6:25252-65. [PMID: 26259235 PMCID: PMC4694829 DOI: 10.18632/oncotarget.4487] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 06/29/2015] [Indexed: 11/25/2022] Open
Abstract
Calcium ions (Ca2+) are indispensable for the physiology of organisms and the molecular regulation of cells. We observed that CGK733, a synthetic chemical substance, induced non-apoptotic cell death and stimulated reversible calcium sequestration by vesicles in pancreatic cancer cells. The endoplasmic reticulum (ER) stress eukaryotic translation initiation factor 2-alpha kinase 3/C/EBP homologous protein (PERK/CHOP) signaling pathway was shown to be activated by treatment with CGK733. Ionomycin, an ER stress drug and calcium ionophore, can activate PERK/CHOP signaling and accelerate CGK733-induced calcium sequestration. Knockdown of CHOP diminished CGK733-induced vesicular calcium sequestration, but had no effects on the cell death. Proteomic analysis demonstrated that the ER-located calcium-binding proteins, calumenin and protein S100-A11, were altered in CGK733-treated cells compared to non-treated controls. Our study reveals that CGK733-induced intracellular calcium sequestration is correlated with the PERK/CHOP signaling pathway and may also be involved in the dysregulations of calcium-binding proteins.
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Affiliation(s)
- Yufeng Wang
- Department of Biochemistry and Functional Proteomics, Yamguchi University Graduate School of Medicine, Ube, Japan
| | - Yasuhiro Kuramitsu
- Department of Biochemistry and Functional Proteomics, Yamguchi University Graduate School of Medicine, Ube, Japan
| | - Byron Baron
- Department of Biochemistry and Functional Proteomics, Yamguchi University Graduate School of Medicine, Ube, Japan
| | - Takao Kitagawa
- Department of Biochemistry and Functional Proteomics, Yamguchi University Graduate School of Medicine, Ube, Japan
| | - Junko Akada
- Department of Biochemistry and Functional Proteomics, Yamguchi University Graduate School of Medicine, Ube, Japan
| | - Kazuhiro Tokuda
- Department of Biochemistry and Functional Proteomics, Yamguchi University Graduate School of Medicine, Ube, Japan
| | - Dan Cui
- Department of Pathology, Yamguchi University Graduate School of Medicine, Ube, Japan
| | - Kazuyuki Nakamura
- Department of Biochemistry and Functional Proteomics, Yamguchi University Graduate School of Medicine, Ube, Japan.,Centre of Clinical Laboratories in Tokuyama Medical Association Hospital, Shunan, Japan
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Nkomba EY, van Rensburg E, Chimphango AFA, Görgens JF. The influence of sorghum grain decortication on bioethanol production and quality of the distillers' dried grains with solubles using cold and conventional warm starch processing. BIORESOURCE TECHNOLOGY 2016; 203:181-9. [PMID: 26724549 DOI: 10.1016/j.biortech.2015.12.045] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/14/2015] [Accepted: 12/15/2015] [Indexed: 05/15/2023]
Abstract
Very high gravity hydrolysis-fermentation of whole and decorticated sorghum grains were compared using conventional and cold hydrolysis methods to assess the extent by which decortication could minimize enzymes dosages and affect the quality of the distillers' dried grains with solubles (DDGS). All processing configurations achieved ethanol concentrations between 126 and 132 g/L (16.0-16.7%v/v), although decortication resulted in a decreased ethanol yield. Decortication resulted in a decreased volumetric productivity during warm processing from 1.55 to 1.25 g L(-1)h(-1), whereas the required enzyme dosage for cold processing was decreased from 250 to 221 μl/100 gstarch. Cold processing decreased the average acid detergent fibre (ADF) from 35.59% to 29.32% and neutral detergent fibre (NDF) from 44.04% to 32.28% in the DDGS compared to the conventional (warm) processing. Due to lower enzyme requirements, the use of decorticated grains combined with cold processing presents a favourable process configuration and source of DDGS for non-ruminants.
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Affiliation(s)
- Edouard Y Nkomba
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Eugéne van Rensburg
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Annie F A Chimphango
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Johann F Görgens
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa.
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Krusong W, Kerdpiboon S, Jindaprasert A, Yaiyen S, Pornpukdeewatana S, Tantratian S. Influence of calcium chloride in the high temperature acetification by strain Acetobacter aceti
WK for vinegar. J Appl Microbiol 2015; 119:1291-300. [DOI: 10.1111/jam.12930] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 07/17/2015] [Accepted: 07/29/2015] [Indexed: 11/27/2022]
Affiliation(s)
- W. Krusong
- Fermentation Technology Division; Faculty of Agro-Industry; King Mongkut's Institute of Technology Ladkrabang; Bangkok Thailand
| | - S. Kerdpiboon
- Food Science and Technology Division; Faculty of Agro-Industry; King Mongkut's Institute of Technology Ladkrabang; Bangkok Thailand
| | - A. Jindaprasert
- Fermentation Technology Division; Faculty of Agro-Industry; King Mongkut's Institute of Technology Ladkrabang; Bangkok Thailand
| | - S. Yaiyen
- Fermentation Technology Division; Faculty of Agro-Industry; King Mongkut's Institute of Technology Ladkrabang; Bangkok Thailand
| | - S. Pornpukdeewatana
- Fermentation Technology Division; Faculty of Agro-Industry; King Mongkut's Institute of Technology Ladkrabang; Bangkok Thailand
| | - S. Tantratian
- Department of Food Technology; Faculty of Science; Chulalongkorn University; Bangkok Thailand
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A structured approach to target starch solubilisation and hydrolysis for the sugarcane industry. Food Chem 2015; 166:165-172. [DOI: 10.1016/j.foodchem.2014.05.151] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 05/28/2014] [Accepted: 05/29/2014] [Indexed: 11/21/2022]
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20
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Tsuji A, Nishiyama N, Ohshima M, Maniwa S, Kuwamura S, Shiraishi M, Yuasa K. Comprehensive enzymatic analysis of the amylolytic system in the digestive fluid of the sea hare, Aplysia kurodai: Unique properties of two α-amylases and two α-glucosidases. FEBS Open Bio 2014; 4:560-70. [PMID: 25161866 PMCID: PMC4141080 DOI: 10.1016/j.fob.2014.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 06/09/2014] [Accepted: 06/12/2014] [Indexed: 12/21/2022] Open
Abstract
The amylolytic system of the digestive fluid of sea hare (Aplysia kurodai) was studied. Two α-amylases and two α-glucosidases were purified from the digestive fluid. Sea hare efficiently digests sea lettuce to glucose by a combination of these enzymes. Starch in sea lettuce is a predominant glucose source for sea hare.
Sea lettuce (Ulva pertusa) is a nuisance species of green algae that is found all over the world. East-Asian species of the marine gastropod, the sea hare Aplysia kurodai, shows a clear feeding preference for sea lettuce. Compared with cellulose, sea lettuce contains a higher amount of starch as a storage polysaccharide. However, the entire amylolytic system in the digestive fluid of A. kurodai has not been studied in detail. We purified α-amylases and α-glucosidases from the digestive fluid of A. kurodai and investigated the synergistic action of these enzymes on sea lettuce. A. kurodai contain two α-amylases (59 and 80 kDa) and two α-glucosidases (74 and 86 kDa). The 59-kDa α-amylase, but not the 80-kDa α-amylase, was markedly activated by Ca2+ or Cl−. Both α-amylases degraded starch and maltoheptaose, producing maltotriose, maltose, and glucose. Glucose production from starch was higher with 80-kDa α-amylase than with 59-kDa α-amylase. Kinetic analysis indicated that 74-kDa α-glucosidase prefers short α-1,4-linked oligosaccharide, whereas 86-kDa α-glucosidase prefers large α-1,6 and α-1,4-linked polysaccharides such as glycogen. When sea lettuce was used as a substrate, a 2-fold greater amount of glucose was released by treatment with 59-kDa α-amylase and 74-kDa α-glucosidase than by treatment with 45-kDa cellulase and 210-kDa β-glucosidase of A. kurodai. Unlike mammals, sea hares efficiently digest sea lettuce to glucose by a combination of two α-amylases and two α-glucosidases in the digestive fluids without membrane-bound maltase–glucoamylase and sucrase–isomaltase complexes.
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Affiliation(s)
- Akihiko Tsuji
- Corresponding author. Tel.: +81 88 656 7526; fax: +81 88 655 3161.
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Singh K, Kayastha AM. Α-amylase from wheat (Triticum aestivum) seeds: its purification, biochemical attributes and active site studies. Food Chem 2014; 162:1-9. [PMID: 24874349 DOI: 10.1016/j.foodchem.2014.04.043] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 03/28/2014] [Accepted: 04/11/2014] [Indexed: 11/18/2022]
Abstract
Glycosylated α-amylase from germinated wheat seeds (Triticum aestivum) has been purified to apparent electrophoretic homogeneity with a final specific activity of 1,372 U/mg. The enzyme preparation when analysed on SDS-PAGE, displayed a single protein band with Mr 33 kDa; Superdex 200 column showed Mr of 32 kDa and MS/MS analysis further provided support for these values. The enzyme displayed its optimum catalytic activity at pH 5.0 and 68 °C with an activation energy of 6.66 kcal/mol and Q10 1.42. The primary substrate for this hydrolase appears to be starch with Km 1.56 mg/mL, Vmax 1666.67 U/mg and kcat 485 s(-1) and hence is suitable for application in starch based industries. Thermal inactivation of α-amylase at 67 °C resulted in first-order kinetics with rate constant (k) 0.0086 min(-1) and t1/2 80 min. The enzyme was susceptible to EDTA (10mM) with irreversible loss of hydrolytic power. In the presence of 1.0mM SDS, the enzyme lost only 14% and 23% activity in 24 and 48 h, respectively. Chemical modification studies showed that the enzyme contains histidine and carboxylic residues at its active site for its catalytic activity and possibly conserved areas.
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Affiliation(s)
- Kritika Singh
- School of Biotechnology, Faculty of Science, Banaras Hindu University, Varanasi 221005, India
| | - Arvind M Kayastha
- School of Biotechnology, Faculty of Science, Banaras Hindu University, Varanasi 221005, India.
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22
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Mohamed SA, Almulaiky YQ, Ahmed YM, Al-Bar OAM, Ibrahim IH. Purification and characterization of α-Amylase from Miswak Salvadora persica. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 14:119. [PMID: 24690287 PMCID: PMC3974154 DOI: 10.1186/1472-6882-14-119] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Accepted: 02/11/2014] [Indexed: 11/29/2022]
Abstract
BACKGROUND The miswak (Salvadora persica) is a natural toothbrush. It is well known that very little information has been reported on enzymes in miswak as medicinal plant. Recently, we study peroxidase in miswak. In the present study, the main goal of this work is to purify and characterize α-amylase from miswak. The second goal is to study the storage stability of α-amylase in toothpaste. METHOD The purification method included chromatography of miswak α-amylase on DEAE-Sepharose column and Sephacryl S-200 column. Molecular weight was determined by gel filtration and SDS-PAGE. RESULTS Five α-amylases A1, A4a, A4b, A5a and A5b from miswak were purified and they had molecular weights of 14, 74, 16, 30 and 20 kDa, respectively. α-Amylases had optimum pH from 6 to 8. Affinity of the substrates toward all enzymes was studied. Miswak α-amylases A1, A4a, A4b, A5a and A5b had Km values for starch and glycogen of 3.7, 3.7, 7.1, 0.52, 4.3 mg/ml and 5.95, 5.9 4.16, 6.3, 6.49 mg/ml, respectively. The optimum temperature for five enzymes ranged 40°C- 60°C. Miswak α-amylases were stable up to 40°C- 60°C after incubation for 30 min. Ca+2 activated all the miswak α-amylases, while Ni2+, Co+2 and Zn+2 activated or inhibited some of these enzymes. The metal chelators, EDTA, sodium citrate and sodium oxalate had inhibitory effects on miswak α-amylases. PMSF, p-HMB, DTNB and 1,10 phenanthroline caused inhibitory effect on α-amylases. The analysis of hydrolytic products after starch hydrolysis by miswak α-amylases on paper chromatography revealed that glucose, maltose, maltotriose and oligosaccharide were the major products. Crude miswak α-amylase in the toothpaste retained 55% of its original activity after 10 months of storage at room temperature. CONCLUSIONS From these findings, α-amylases from miswak can be considered as beneficial enzymes for pharmaceuticals. Therefore, we study the storage stability of the crude α-amylase of miswak, which contained the five α-amylases, in toothpaste. The enzyme in the toothpaste retained 55% of its original activity after 10 months of storage at room temperature.
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Affiliation(s)
- Saleh A Mohamed
- Biochemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Kingdom of Saudi Arabia
- Molecular Biology Department, National Research Center, Dokki, Cairo, Egypt
| | - Yaaser Q Almulaiky
- Biochemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Kingdom of Saudi Arabia
- Chemistry Department, Faculty of Science, Taiz University, Taiz, Yemen
| | - Youssri M Ahmed
- Biochemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Kingdom of Saudi Arabia
| | - Omar AM Al-Bar
- Biochemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Kingdom of Saudi Arabia
| | - Ibrahim H Ibrahim
- Biochemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Kingdom of Saudi Arabia
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TIMMERS ANTONIUSCJ, KIEFT HENK, SCHEL JANHN. An immunofluorescence study on calmodulin distribution during somatic and zygotic embryogenesis of carrot (Daucus carotaL.). ACTA ACUST UNITED AC 2013. [DOI: 10.1111/j.1438-8677.1995.tb00765.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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25
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Nwagu TN, Okolo B, Aoyagi H, Yoshida S. Improved yield and stability of amylase by multipoint covalent binding on polyglutaraldehyde activated chitosan beads: Activation of denatured enzyme molecules by calcium ions. Process Biochem 2013. [DOI: 10.1016/j.procbio.2013.05.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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26
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Nasir MN, Laurent P, Flore C, Lins L, Ongena M, Deleu M. Analysis of calcium-induced effects on the conformation of fengycin. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 110:450-457. [PMID: 23588300 DOI: 10.1016/j.saa.2013.03.063] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 03/08/2013] [Accepted: 03/10/2013] [Indexed: 06/02/2023]
Abstract
Fengycin is a natural lipopeptide with antifungal and eliciting properties and able to inhibit the activity of phospholipase A2. A combination of CD, FT-IR, NMR and fluorescence spectroscopic techniques was applied to elucidate its conformation in a membrane-mimicking environment and to investigate the effect of calcium ions on it. We mainly observed that fengycin adopts a turn conformation. Our results showed that calcium ions are bound by the two charged glutamates. The calcium binding has an influence on the fengycin conformation and more particularly, on the environment of the tyrosine residues. The modulation of the fengycin conformation by the environmental conditions may influence its biological properties.
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Affiliation(s)
- Mehmet Nail Nasir
- Unité de Chimie biologique industrielle, University of Liege, Passage des Déportés, 2, 5030 Gembloux, Belgium
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Rana N, Walia A, Gaur A. α-Amylases from Microbial Sources and Its Potential Applications in Various Industries. NATIONAL ACADEMY SCIENCE LETTERS-INDIA 2013. [DOI: 10.1007/s40009-012-0104-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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28
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Presečki AV, Blažević ZF, Vasić-Rački Đ. Mathematical modeling of maize starch liquefaction catalyzed by α-amylases from Bacillus licheniformis: effect of calcium, pH and temperature. Bioprocess Biosyst Eng 2012; 36:117-26. [DOI: 10.1007/s00449-012-0767-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 06/01/2012] [Indexed: 11/24/2022]
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29
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Vriesekoop F, Rathband A, MacKinlay J, Bryce JH. The Evolution of Dextrins During the Mashing and Fermentation of All-malt Whisky Production. JOURNAL OF THE INSTITUTE OF BREWING 2012. [DOI: 10.1002/j.2050-0416.2010.tb00425.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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30
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Stable expression of barley α-amylase in S. cerevisiae for conversion of starch into bioethanol. Biochem Eng J 2012. [DOI: 10.1016/j.bej.2012.02.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Yadav JK. A differential behavior of α-amylase, in terms of catalytic activity and thermal stability, in response to higher concentration CaCl2. Int J Biol Macromol 2012; 51:146-52. [PMID: 22542853 DOI: 10.1016/j.ijbiomac.2012.04.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 04/08/2012] [Accepted: 04/12/2012] [Indexed: 11/28/2022]
Abstract
A differential relationship was observed between thermal stability and catalytic activity of α-amylase in the presence of different concentrations of CaCl(2). The enzyme displays optimum catalytic activity in the presence of 1.0-2.0 mM CaCl(2). Further addition of CaCl(2) leads to inhibition of the enzyme, however, at the same time the enzyme gains an additional resistance against thermal denaturation. It was evident that the enzyme is thermodynamically more stable (compared to the active enzyme) in the presence of inhibitory concentration of CaCl(2). For example, the thermal transition temperature (T(m)) of optimally active α-amylase was found to be 64±1°C, whereas, for the less active enzyme (in the presence 10 mM CaCl(2)) the value was determined to be 71±1°C. Similarly, the activation energy of thermal inactivation (Ea) was found to be 228±12 kJ/mol and 291±15 kJ/mol for the optimally active enzyme and the enzyme in the presence of 10 mM CaCl(2), respectively. Biophysical analysis of different states of the enzymes in response to variable calcium level indicates no significant change in the secondary structure in response to different concentration of CaCl(2), however the less active but thermodynamically stable enzyme (in the presence of higher concentration of CaCl(2)) was shown to have relatively more compact structure. The results suggest that the enzyme has separate catalytic and structure stabilizing domains and they significantly vary in their functional attributes in response to calcium level.
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Affiliation(s)
- Jay Kant Yadav
- Department of Protein Chemistry and Technology, Central Food Technological Research Institute, Mysore, India.
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32
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Production, purification and characterization of two α-amylase isoforms from a newly isolated Aspergillus Oryzae strain S2. Process Biochem 2012. [DOI: 10.1016/j.procbio.2011.09.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Impact of Calcium on Salivary α-Amylase Activity, Starch Paste Apparent Viscosity, and Thickness Perception. CHEMOSENS PERCEPT 2011. [DOI: 10.1007/s12078-011-9091-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Duncan JR, Lawrence AJ. The role of metabotropic glutamate receptors in addiction: evidence from preclinical models. Pharmacol Biochem Behav 2011; 100:811-24. [PMID: 21443897 DOI: 10.1016/j.pbb.2011.03.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 02/21/2011] [Accepted: 03/16/2011] [Indexed: 11/25/2022]
Abstract
Addiction is a chronic disorder characterised by repeated bouts of drug taking, abstinence and relapse. The addicted state may be in part due to drug-induced neuroadaptations in the mesocorticolimbic and corticostriatal pathways. Recently focus has been on the role of aberrant glutamate transmission and its contribution to the hierarchical control over these systems. This review will expand our current knowledge of the most recent advances that have been made in preclinical animal models that provide evidence that implicate metabotropic glutamate receptors (mGluRs) in contributing to the neuroadaptations pertinent to addiction, as well as the role of Homer proteins in regulating these responses. The recent discovery of receptor mosaics will be discussed which add an additional dimension to the complexity of understanding the mechanism of glutamate mediated behaviours. Finally this review introduces a new area related to glutamatergic responses, namely microRNAs, that may become pivotal in directing our future understanding of how to best target intervention strategies to prevent addictive behaviours.
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Affiliation(s)
- Jhodie R Duncan
- Florey Neuroscience Institutes, University of Melbourne, Parkville, Vic., 3010, Australia.
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35
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Li S, Zuo Z, Niu D, Singh S, Permaul K, Prior BA, Shi G, Wang Z. Gene cloning, heterologous expression, and characterization of a high maltose-producing α-amylase of Rhizopus oryzae. Appl Biochem Biotechnol 2011; 164:581-92. [PMID: 21243443 DOI: 10.1007/s12010-011-9159-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2010] [Accepted: 01/04/2011] [Indexed: 11/27/2022]
Abstract
A putative α-amylase gene, designated as RoAmy, was cloned from Rhizopus oryzae. The deduced amino acid sequence showed the highest (42.8%) similarity to the α-amylase from Trichoderma viride. The RoAmy gene was successfully expressed in Pichia pastoris GS115 under the induction of methanol. The molecular weight of the purified RoAmy determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis was approximately 48 kDa. The optimal pH and temperature were 4-6 and 60 °C, respectively. The enzyme was stable at pH ranges of 4.5-6.5 and temperatures below 50 °C. Purified RoAmy had a K(m) and V(max) of 0.27 mg/ml and 0.068 mg/min, respectively, with a specific activity of 1,123 U/mg on soluble starch. Amylase activity was strongly inhibited by 5 mM Cu(2+) and 5 mM Fe(2+), whereas 5 mM Ca(2+) showed no significant effect. The RoAmy hydrolytic activity was the highest on wheat starch but showed only 55% activity on amylopectin relative to soluble corn starch, while the pullulanase activity was negligible. The main end products of the polysaccharides tested were glucose and maltose. Maltose reached a concentration of 74% (w/w) with potato starch as the substrate. The enzyme had an extremely high affinity (K(m) = 0.22 mM) to maltotriose. A high ratio of glucose/maltose of 1:4 was obtained when maltotriose was used at an initial concentration of 40 mM.
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Affiliation(s)
- Song Li
- Research Center of Bioresource & Bioenergy, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
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Bozonnet S, Kim TJ, Bønsager BC, Kramhøft B, Nielsen PK, Bak-Jensen KS, Svensson B. Engineering of Barley α-Amylase. BIOCATAL BIOTRANSFOR 2010. [DOI: 10.1080/10242420310001618564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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37
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Mohamed SA, Drees EA, El-Badry MO, Fahmy AS. Biochemical Properties of α-Amylase from Peel of Citrus sinensis cv. Abosora. Appl Biochem Biotechnol 2009; 160:2054-65. [DOI: 10.1007/s12010-009-8864-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Accepted: 11/09/2009] [Indexed: 10/20/2022]
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Nielsen MM, Seo ES, Dilokpimol A, Andersen J, Abou Hachem M, Naested H, Willemoës M, Bozonnet S, Kandra L, Gyémánt G, Haser R, Aghajari N, Svensson B. Roles of multiple surface sites, long substrate binding clefts, and carbohydrate binding modules in the action of amylolytic enzymes on polysaccharide substrates. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.1080/10242420701789528] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Hachem MA, Bozonnet S, Willemoës M, Kramhøft B, Fukuda K, Bønsager BC, Jensen MT, Nøhr J, Tranier S, Juge N, Robert X, Haser R, Aghajari N, Svensson B. Interactions of barley α-amylase isozymes with Ca2 + , substrates and proteinaceous inhibitors. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.1080/10242420500516163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Anitha Gopal B, Muralikrishna G. Porcine Pancreatic α-Amylase and its Isoforms: Purification and Kinetic Studies. INTERNATIONAL JOURNAL OF FOOD PROPERTIES 2009. [DOI: 10.1080/10942910801947755] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Ben Elarbi M, Khemiri H, Jridi T, Ben Hamida J. Purification and characterization of alpha-amylase from safflower (Carthamus tinctorius L.) germinating seeds. C R Biol 2009; 332:426-32. [PMID: 19393974 DOI: 10.1016/j.crvi.2009.01.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 01/07/2009] [Indexed: 11/28/2022]
Abstract
alpha-Amylase (alpha-1-4 D-glucan glucanohydrolase EC 3.2.1.1) crude extract was obtained from safflower (Carthamus tinctorius L.) cotyledons excised from 5-day-old dark grown seedlings. The enzyme was purified by precipitating the crude extract with ammonium sulphate at 20-60% saturation, and then by subjecting this fraction to affinity chromatography on a beta-cyclodextrin-Sepharose 6B column. The active fraction was dialysed and concentrated. An overall purification of about 131 folds with an activity yield of 81.25% was achieved. The molecular mass of purified enzyme determined by SDS-PAGE was 35 kD. When the purified alpha-amylase was subjected to gel electrophoresis followed by negative staining, only one band of active protein was detected. Its maximal activity was in the pH 6.0 and at a temperature of 55 degrees C. This enzyme was activated by Ca(2+) and inhibited by Fe(2+).
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Conformational stability and integrity of α-amylase from mung beans: Evidence of kinetic intermediate in GdmCl-induced unfolding. Biophys Chem 2008; 137:95-9. [DOI: 10.1016/j.bpc.2008.07.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 07/16/2008] [Accepted: 07/24/2008] [Indexed: 11/20/2022]
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Choi SH, Yuk JB, Jang MU, Park JM, Yi AR, Svensson B, Kim TJ. Expression profiles of barley alpha-amylase isozymes in various Escherichia coli systems. J Biotechnol 2008. [DOI: 10.1016/j.jbiotec.2008.07.1961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pan YT, Carroll JD, Asano N, Pastuszak I, Edavana VK, Elbein AD. Trehalose synthase converts glycogen to trehalose. FEBS J 2008; 275:3408-20. [PMID: 18505459 DOI: 10.1111/j.1742-4658.2008.06491.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Trehalose (alpha,alpha-1,1-glucosyl-glucose) is essential for the growth of mycobacteria, and these organisms have three different pathways that can produce trehalose. One pathway involves the enzyme described in the present study, trehalose synthase (TreS), which interconverts trehalose and maltose. We show that TreS from Mycobacterium smegmatis, as well as recombinant TreS produced in Escherichia coli, has amylase activity in addition to the maltose <--> trehalose interconverting activity (referred to as MTase). Both activities were present in the enzyme purified to apparent homogeneity from extracts of Mycobacterium smegmatis, and also in the recombinant enzyme produced in E. coli from either the M. smegmatis or the Mycobacterium tuberculosis gene. Furthermore, when either purified or recombinant TreS was chromatographed on a Sephacryl S-200 column, both MTase and amylase activities were present in the same fractions across the peak, and the ratio of these two activities remained constant in these fractions. In addition, crystals of TreS also contained both amylase and MTase activities. TreS produced both radioactive maltose and radioactive trehalose when incubated with [(3)H]glycogen, and also converted maltooligosaccharides, such as maltoheptaose, to both maltose and trehalose. The amylase activity was stimulated by addition of Ca(2+), but this cation inhibited the MTase activity. In addition, MTase activity, but not amylase activity, was strongly inhibited, and in a competitive manner, by validoxylamine. On the other hand, amylase, but not MTase activity, was inhibited by the known transition-state amylase inhibitor, acarbose, suggesting the possibility of two different active sites. Our data suggest that TreS represents another pathway for the production of trehalose from glycogen, involving maltose as an intermediate. In addition, the wild-type organism or mutants blocked in other trehalose biosynthetic pathways, but still having active TreS, accumulate 10- to 20-fold more glycogen when grown in high concentrations (> or = 2% or more) of trehalose, but not in glucose or other sugars. Furthermore, trehalose mutants that are missing TreS do not accumulate glycogen in high concentrations of trehalose or other sugars. These data indicate that trehalose and TreS are both involved in the production of glycogen, and that the metabolism of trehalose and glycogen is interconnected.
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Affiliation(s)
- Yuan-Tseng Pan
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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Buckow R, Weiss U, Heinz V, Knorr D. Stability and catalytic activity of alpha-amylase from barley malt at different pressure-temperature conditions. Biotechnol Bioeng 2007; 97:1-11. [PMID: 17013936 DOI: 10.1002/bit.21209] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The impact of high hydrostatic pressure and temperature on the stability and catalytic activity of alpha-amylase from barley malt has been investigated. Inactivation experiments with alpha-amylase in the presence and absence of calcium ions have been carried out under combined pressure-temperature treatments in the range of 0.1-800 MPa and 30-75 degrees C. A stabilizing effect of Ca(2+) ions on the enzyme was found at all pressure-temperature combinations investigated. Kinetic analysis showed deviations of simple first-order reactions which were attributed to the presence of isoenzyme fractions. Polynomial models were used to describe the pressure-temperature dependence of the inactivation rate constants. Derived from that, pressure-temperature isokinetic diagrams were constructed, indicating synergistic and antagonistic effects of pressure and temperature on the inactivation of alpha-amylase. Pressure up to 200 MPa significantly stabilized the enzyme against temperature-induced inactivation. On the other hand, pressure also hampers the catalytic activity of alpha-amylase and a progressive deceleration of the conversion rate was detected at all temperatures investigated. However, for the overall reaction of blocked p-nitrophenyl maltoheptaoside cleavage and simultaneous occurring enzyme inactivation in ACES buffer (0.1 M, pH 5.6, 3.8 mM CaCl(2)), a maximum of substrate cleavage was identified at 152 MPa and 64 degrees C, yielding approximately 25% higher substrate conversion after 30 min, as compared to the maximum at ambient pressure and 59 degrees C.
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Affiliation(s)
- Roman Buckow
- Department of Food Biotechnology and Food Process Engineering, Berlin University of Technology, Koenigin-Luise-Str. 22, D-14195 Berlin, Germany
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Bak-Jensen KS, Laugesen S, Ostergaard O, Finnie C, Roepstorff P, Svensson B. Spatio-temporal profiling and degradation of α-amylase isozymes during barley seed germination. FEBS J 2007; 274:2552-65. [PMID: 17437525 DOI: 10.1111/j.1742-4658.2007.05790.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ten genes from two multigene families encode barley alpha-amylases. To gain insight into the occurrence and fate of individual isoforms during seed germination, the alpha-amylase repertoire was mapped by using a proteomics approach consisting of 2D gel electrophoresis, western blotting, and mass spectrometry. Mass spectrometric analysis confirmed that the 29 alpha-amylase positive 2D gel spots contained products of one (GenBank accession gi|113765) and two (gi|4699831 and gi|166985) genes encoding alpha-amylase 1 and 2, respectively, but lacked products from seven other genes. Eleven spots were identified only by immunostaining. Mass spectrometry identified 12 full-length forms and 12 fragments from the cultivar Barke. Products of both alpha-amylase 2 entries co-migrated in five full-length and one fragment spot. The alpha-amylase abundance and the number of fragments increased during germination. Assessing the fragment minimum chain length by peptide mass fingerprinting suggested that alpha-amylase 2 (gi|4699831) initially was cleaved just prior to domain B that protrudes from the (betaalpha)(8)-barrel between beta-strand 3 and alpha-helix 3, followed by cleavage on the C-terminal side of domain B and near the C-terminus. Only two shorter fragments were identified of the other alpha-amylase 2 (gi|166985). The 2D gels of dissected tissues showed alpha-amylase degradation to be confined to endosperm. In contrast, the aleurone layer contained essentially only full-length alpha-amylase forms. While only products of the above three genes appeared by germination also of 15 other barley cultivars, the cultivars had distinct repertoires of charge and molecular mass variant forms. These patterns appeared not to be correlated with malt quality.
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Kang HK, Lee JH, Kim D, Day DF, Robyt JF, Park KH, Moon TW. Cloning and expression of Lipomyces starkeyi alpha-amylase in Escherichia coli and determination of some of its properties. FEMS Microbiol Lett 2004; 233:53-64. [PMID: 15043869 DOI: 10.1016/j.femsle.2004.01.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2003] [Revised: 01/16/2004] [Accepted: 01/21/2004] [Indexed: 10/26/2022] Open
Abstract
The Lipomyces starkeyi alpha-amylase (LSA) gene encoding soluble starch-degrading alpha-amylase was cloned and characterized from a derepressed and partially constitutive mutant for both dextranase and amylase activities. The nucleotide (nt) sequence of the cDNA fragment reveals an open reading frame of 1944 bp encoding a 619 amino acid (aa) mature protein (LSA) with a calculated molecular weight of 68.709 kDa that was estimated to be about 73 kDa, including His tag (4 kDa) based on SDS-PAGE (10% acrylamide gel), activity staining, and the Western blotting, using anti-amylase-Ab. LSA had a sequence similar to other alpha-amylases in four conserved regions of the alpha-amylase family: (I) (287)DIVVNH(292), (II) (372)GLRIDTVKH(380), (III) (399)GEVFD(403), (IV) (462)FLENQD(467). Polymerase chain reaction and sequence analysis showed one intron of 60 nucleotides in the genomic lsa at positions between 966 and 967 of cDNA. The cloned LSA amylase showed a maximum activity at pH 6 and optimum temperature of 40 (o)C, with greater than 90% stability between pH 5 and pH 8 for 16 h. It was inhibited by Cu(2+) and stimulated by Ca(2+) and Mg(2+). Enzyme activity was not affected by 1 mM EGTA but was inhibited by 1 mM EDTA. LSA did not hydrolyze maltodextrins of G2 to G4, yet formed G2+G3 from G5, G2+G4 or G3+G3 from G6, and G3+G4 from G7. LSA did not hydrolyze soluble starch in the present of 2% (w/v) of acarbose. Kinetics of LSA was carried out by using starch as a substrate and the inhibition type of acarbose was the mixed non-competitive type (ki = 3.4 microM).
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Affiliation(s)
- Hee Kyoung Kang
- Laboratory of Functional Carbohydrate Enzymes and Microbial Genomics, Chonnam National University, Gwang-Ju, South Korea
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Nielsen PK, Bønsager BC, Fukuda K, Svensson B. Barley α-amylase/subtilisin inhibitor: structure, biophysics and protein engineering. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2004; 1696:157-64. [PMID: 14871656 DOI: 10.1016/j.bbapap.2003.09.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2003] [Accepted: 09/11/2003] [Indexed: 10/26/2022]
Abstract
Bifunctional alpha-amylase/subtilisin inhibitors have been implicated in plant defence and regulation of endogenous alpha-amylase action. The barley alpha-amylase/subtilisin inhibitor (BASI) inhibits the barley alpha-amylase 2 (AMY2) and subtilisin-type serine proteases. BASI belongs to the Kunitz-type trypsin inhibitor family of the beta-trefoil fold proteins. Diverse approaches including site-directed mutagenesis, hybrid constructions, and crystallography have been used to characterise the structures and contact residues in the AMY2/BASI complex. The three-dimensional structure of the AMY2/BASI complex is characterised by a completely hydrated Ca2+ situated at the protein interface that connects the three catalytic carboxyl groups in AMY2 with side chains in BASI via water molecules. Using surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC), we have recently demonstrated Ca2+-modulated kinetics of the AMY2/BASI interaction and found that the complex formation involves minimal structural changes. The modulation of the interaction by calcium ions makes it unique among the currently known binding mechanisms of proteinaceous alpha-amylase inhibitors.
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Affiliation(s)
- Peter K Nielsen
- Carlsberg Laboratory, Department of Chemistry, Gamle Carlsberg Vej 10 Valby, DK-2500 Copenhagen, Denmark
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Nielsen AD, Pusey ML, Fuglsang CC, Westh P. A proposed mechanism for the thermal denaturation of a recombinant Bacillus halmapalus α-amylase—the effect of calcium ions. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2003; 1652:52-63. [PMID: 14580996 DOI: 10.1016/j.bbapap.2003.08.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The thermal stability of a recombinant alpha-amylase from Bacillus halmapalus alpha-amylase (BHA) has been investigated using circular dichroism spectroscopy (CD) and differential scanning calorimetry (DSC). This alpha-amylase is homologous to other Bacillus alpha-amylases where crystallographic studies have identified the existence of three calcium binding sites in the structure. Denaturation of BHA is irreversible with a T(m) of approximately 89 degrees C and DSC thermograms can be described using a one-step irreversible model. A 5 degrees C increase in T(m) in the presence of 10-fold excess CaCl(2) was observed. However, a concomitant increase in the tendency to aggregate was also observed. The presence of 30-40-fold excess calcium chelator (ethylenediaminetetraacetic acid (EDTA) or ethylene glycol-bis[beta-aminoethyl ether] N,N,N',N'-tetraacetic acid (EGTA)) results in a large destabilization of BHA, corresponding to about 40 degrees C lower T(m) as determined by both CD and DSC. Ten-fold excess EGTA reveals complex DSC thermograms corresponding to both reversible and irreversible transitions, which probably originate from different populations of BHA/calcium complexes. Combined interpretation of these observations and structural information on homologous alpha-amylases forms the basis for a suggested mechanism underlying the inactivation mechanism of BHA. The mechanism includes irreversible thermal denaturation of different BHA/calcium complexes and the calcium binding equilibria. Furthermore, the model accounts for a temperature-induced reversible structural change associated with calcium binding.
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Affiliation(s)
- Anders D Nielsen
- Department of Life Sciences and Chemistry, Roskilde University, P.O. Box 260, 1-Universitetsvej, DK-4000 Roskilde, Denmark
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