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Sample records for patients alpha-amylase inhibitors

  1. Proteinaceous alpha-amylase inhibitors.

    PubMed

    Svensson, Birte; Fukuda, Kenji; Nielsen, Peter K; Bønsager, Birgit C

    2004-02-12

    Proteins that inhibit alpha-amylases have been isolated from plants and microorganisms. These inhibitors can have natural roles in the control of endogenous alpha-amylase activity or in defence against pathogens and pests; certain inhibitors are reported to be antinutritional factors. The alpha-amylase inhibitors belong to seven different protein structural families, most of which also contain evolutionary related proteins without inhibitory activity. Two families include bifunctional inhibitors acting both on alpha-amylases and proteases. High-resolution structures are available of target alpha-amylases in complex with inhibitors from five families. These structures indicate major diversity but also some similarity in the structural basis of alpha-amylase inhibition. Mutational analysis of the mechanism of inhibition was performed in a few cases and various protein engineering and biotechnological approaches have been outlined for exploitation of the inhibitory function. PMID:14871655

  2. Zinc oxide nanoparticles as novel alpha-amylase inhibitors

    NASA Astrophysics Data System (ADS)

    Dhobale, Sandip; Thite, Trupti; Laware, S. L.; Rode, C. V.; Koppikar, Soumya J.; Ghanekar, Ruchika-Kaul; Kale, S. N.

    2008-11-01

    Amylase inhibitors, also known as starch blockers, contain substances that prevent dietary starches from being absorbed by the body via inhibiting breakdown of complex sugars to simpler ones. In this sense, these materials are projected as having potential applications in diabetes control. In this context, we report on zinc oxide nanoparticles as possible alpha-amylase inhibitors. Zinc oxide nanoparticles have been synthesized using soft-chemistry approach and 1-thioglycerol was used as a surfactant to yield polycrystalline nanoparticles of size ˜18 nm, stabilized in wurtzite structure. Conjugation study and structural characterization have been done using x-ray diffraction technique, Fourier transform infrared spectroscopy, UV-visible spectroscopy, and transmission electron microscopy. Cytotoxicity studies on human fibrosarcoma (HT-1080) and skin carcinoma (A-431) cell lines as well as mouse primary fibroblast cells demonstrate that up to a dose of 20 μg/ml, ZnO nanoparticles are nontoxic to the cells. We report for the first time the alpha-amylase inhibitory activity of ZnO nanoparticles wherein an optimum dose of 20 μg/ml was sufficient to exhibit 49% glucose inhibition at neutral pH and 35 °C temperature. This inhibitory activity was similar to that obtained with acarbose (a standard alpha-amylase inhibitor), thereby projecting ZnO nanoparticles as novel alpha-amylase inhibitors.

  3. A chimera-like alpha-amylase inhibitor suggesting the evolution of Phaseolus vulgaris alpha-amylase inhibitor.

    PubMed

    Wato, S; Kamei, K; Arakawa, T; Philo, J S; Wen, J; Hara, S; Yamaguchi, H

    2000-07-01

    White kidney bean (Phaseolus vulgaris) contains two kinds of alpha-amylase inhibitors, one heat-stable (alpha AI-s) and one heat-labile (alpha AI-u). alpha AI-s has recently been revealed to be a tetrameric complex, alpha(2)beta(2), with two active sites [Kasahara et al. (1996) J. Biochem. 120, 177-183]. The present study was undertaken to reveal the molecular features of alpha AI-u, which is composed of three kinds of subunits, alpha, beta, and gamma. The gamma-subunit, in contrast to the alpha- and beta-subunits that are indistinguishable from the alpha- and beta-subunits of alpha AI-s, was found to correspond to a subunit of an alpha-amylase inhibitor-like protein, which has been identified as an inactive, evolutionary intermediate between arcelin and the alpha-amylase inhibitor in a P. vulgaris defense protein family. The polypeptide molecular weight of alpha AI-u determined by the light-scattering technique, together with the polypeptide molecular weights of the subunits, suggests that alpha AI-u is a trimeric complex, alpha beta gamma. The inhibition of alpha AI-u by increasing amounts of porcine pancreatic alpha-amylase (PPA) indicates that an inactive 1:1 complex is formed between alpha AI-u and PPA. Molecular weight estimation of the complex by the light-scattering technique confirmed that it is a complex of alpha AI-u with one PPA molecule. Thus it seems probable that alpha AI-u is an evolutionary intermediate of the P. vulgaris alpha-amylase inhibitor. PMID:10876168

  4. Cross-inhibitory activity of cereal protein inhibitors against alpha-amylases and xylanases.

    PubMed

    Sancho, Ana I; Faulds, Craig B; Svensson, Birte; Bartolomé, Begoña; Williamson, Gary; Juge, Nathalie

    2003-08-21

    The purification and characterisation of a xylanase inhibitor (XIP-I) from wheat was reported previously. In our current work, XIP-I is also demonstrated to have the capacity to inhibit the two barley alpha-amylase isozymes (AMY1 and AMY2). XIP-I completely inhibited the activity of AMY1 and AMY2 towards insoluble Blue Starch and a soluble hepta-oligosaccharide derivative. A ternary complex was formed between insoluble starch, a catalytically inactive mutant of AMY1 (D180A), and XIP-I, suggesting that the substrate-XIP-I interaction is necessary for inhibition of barley alpha-amylases. K(i) values for alpha-amylase inhibition, however, could not be calculated due to the nonlinear nature of the inhibition pattern. Furthermore, surface plasmon resonance and gel electrophoresis did not indicate interaction between XIP-I and the alpha-amylases. The inhibition was abolished by CaCl(2), indicating that the driving force for the interaction is different from that of complexation between the barley alpha-amylase/subtilisin inhibitor (BASI) and AMY2. This is the first report of a proteinaceous inhibitor of AMY1. BASI, in addition, was demonstrated to partially inhibit the endo-1,4-beta-D-xylanase from Aspergillus niger (XylA) of glycoside hydrolase family 11. Taken together, the data demonstrate for the first time the dual target enzyme specificity of BASI and XIP-I inhibitors for xylanase and alpha-amylase. PMID:12922177

  5. Barley alpha-amylase/subtilisin inhibitor: structure, biophysics and protein engineering.

    PubMed

    Nielsen, Peter K; Bønsager, Birgit C; Fukuda, Kenji; Svensson, Birte

    2004-02-12

    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. PMID:14871656

  6. A lectin gene encodes the alpha-amylase inhibitor of the common bean.

    PubMed Central

    Moreno, J; Chrispeels, M J

    1989-01-01

    An alpha-amylase inhibitor that inhibits insect and mammalian alpha-amylases but not plant alpha-amylases, is present in seeds of the common bean (Phaseolus vulgaris). We have purified the alpha-amylase inhibitor by using a selective heat treatment in acidic medium and affinity chromatography with porcine pancreas alpha-amylase coupled to agarose. Under sodium dodecyl sulfate gel electrophoresis, the purified inhibitor gave rise to five bands with mobilities corresponding to molecular masses ranging from 14 to 19 kDa. N-terminal sequencing (up to 15 amino acids) of the polypeptides obtained from these bands resulted in only two different sequences matching two stretches of the amino acid sequence deduced from an already described lectin gene [Hoffman, L. M. (1984) J. Mol. Appl. Gen. 2,447-453]. This gene is different from but closely related to the genes that code for phytohemagglutinin, the major lectin of bean. Further evidence based on amino acid composition, identification of a precursor, and recognition of the product of the gene (expressed in Escherichia coli) by an anti-alpha-amylase inhibitor serum confirms that the inhibitor is encoded by this or a closely related lectin gene. This finding assigns a biological function, which has been described at the molecular level, to a plant lectin gene product and supports the defense role postulated for seed lectins. The lack of homology with other families of enzyme inhibitors suggests that this may be the first member of a new family of plant enzyme inhibitors. Images PMID:2682631

  7. Differentiation of alpha-amylase from various sources: an approach using selective inhibitors.

    PubMed

    Quarino, L; Hess, J; Shenouda, M; Ristenbatt, R R; Gold, J; Shaler, R C

    1993-01-01

    A radial diffusion assay in an agarose/starch gel utilizing crude kidney bean extract and a commercially prepared alpha-amylase inhibitor isolated from wheat seeds was developed and assessed to determine its ability to differentiate alpha-amylase from various sources. Kidney bean extract was found to have a greater inhibitory effect on AMY2, while the wheat lectin inhibitor was found to have a greater inhibitory effect on AMY1. Neither inhibitor was found to have any effect on commercially prepared bacterial alpha-amylase extract in both liquid preparations and dried stains. Mixtures of varying concentrations of pancreatic and salivary extracts also gave interpretable results. Additionally, dried stains prepared from human body fluids having high levels of AMY2 were differentiated from dried stains prepared from human body fluids containing high levels of AMY1. PMID:8360608

  8. The bean. alpha. -amylase inhibitor is encoded by a lectin gene

    SciTech Connect

    Moreno, J.; Altabella, T.; Chrispeels, M.J. )

    1989-04-01

    The common bean, Phaseolus vulgaris, contains an inhibitor of insect and mammalian {alpha}-amylases that does not inhibit plant {alpha}-amylase. This inhibitor functions as an anti-feedant or seed-defense protein. We purified this inhibitor by affinity chromatography and found that it consists of a series of glycoforms of two polypeptides (Mr 14,000-19,000). Partial amino acid sequencing was carried out, and the sequences obtained are identical with portions of the derived amino acid sequence of a lectin-like gene. This lectin gene encodes a polypeptide of MW 28,000, and the primary in vitro translation product identified by antibodies to the {alpha}-amylase inhibitor has the same size. Co- and posttranslational processing of this polypeptide results in glycosylated polypeptides of 14-19 kDa. Our interpretation of these results is that the bean lectins constitute a gene family that encodes diverse plant defense proteins, including phytohemagglutinin, arcelin and {alpha}-amylase inhibitor.

  9. Crystal structures of human pancreatic alpha-amylase in complex with carbohydrate and proteinaceous inhibitors.

    PubMed Central

    Nahoum, V; Roux, G; Anton, V; Rougé, P; Puigserver, A; Bischoff, H; Henrissat, B; Payan, F

    2000-01-01

    Crystal structures of human pancreatic alpha-amylase (HPA) in complex with naturally occurring inhibitors have been solved. The tetrasaccharide acarbose and a pseudo-pentasaccharide of the trestatin family produced identical continuous electron densities corresponding to a pentasaccharide species, spanning the -3 to +2 subsites of the enzyme, presumably resulting from transglycosylation. Binding of the acarviosine core linked to a glucose residue at subsites -1 to +2 appears to be a critical part of the interaction process between alpha-amylases and trestatin-derived inhibitors. Two crystal forms, obtained at different values of pH, for the complex of HPA with the protein inhibitor from Phaseolus vulgaris (alpha-amylase inhibitor) have been solved. The flexible loop typical of the mammalian alpha-amylases was shown to exist in two different conformations, suggesting that loop closure is pH-sensitive. Structural information is provided for the important inhibitor residue, Arg-74, which has not been observed previously in structural analyses. PMID:10657258

  10. Structural studies of wheat monomeric and dimeric protein inhibitors of alpha-amylase.

    PubMed Central

    Petrucci, T; Sannia, G; Parlamenti, R; Silano, V

    1978-01-01

    Two wheat monomeric protein inhibitors of alpha-amylase with mol.wt. 12000, designated inhibitors 0.28 and 0.39 according to their gel-electrophoretic mobilities, showed almost identical circular-dichroism spectra in both the far and near u.v. at different pH values as well as in the presence or absence of dissociating and reducing agents. Both inhibitors (0.28 and 0.39) were readily inactivated by reduction of the five disulphide bridges present in each inhibitor molecule. These properties are very similar to those exhibited by the wheat dimeric protein inhibitor of alpha-amylase with mol.wt. 24000, designated inhibitor 0.19 according to its gel-electrophoretic mobility. The N-terminal sequence of the 0.19 inhibitor was determined without separating its subunits and compared with that of the 0.28 inhibitor reported by Redman [(1976) Biochem. J. 155, 193--195]. Petide 'maps' from tryptic digests of reduced and carboxymethylated inhibitors 0.19 and 0.28 were compared. One molecule of reducing sugar is covalently bound per inhibitor-0.19 protomer and inhibitor-0.28 molecule. The results obtained strongly support previous findings indicating the structural equivalence of inhibitor 0.28 with each inhibitor-0.19 protomer and the common phylogenetic origin of these protein alpha-amylase inhibitors from wheat kernel. PMID:308369

  11. Insecticidal activity of an alpha-amylase inhibitor-like protein resembling a putative precursor of alpha-amylase inhibitor in the common bean, Phaseolus vulgaris L.

    PubMed

    Ishimoto, M; Yamada, T; Kaga, A

    1999-06-15

    alpha-Amylase inhibitor (alphaAI) in the common bean, Phaseolus vulgaris L., protects seeds from insect pests such as the cowpea weevil (Callosobruchus maculatus) and the azuki bean weevil (C. chinensis). Cultivars which lack alphaAI still show resistance to both bruchids. These cultivars have a glycoprotein that reacts with anti-alphaAI-1 antibodies. The glycoprotein with a molecular mass of 29 kDa (Gp29) was purified and the encoding gene was isolated. The primary structure of Gp29 is the same as alpha-amylase inhibitor-like protein (AIL) from which the encoding gene has already been isolated. AIL resembles a putative precursor of alphaAI, even though it does not form the active inhibitor. However, AIL has some inhibitory effect on the growth of C. maculatus but not C. chinensis. The presence of AIL alone is insufficient to explain the bruchid resistance of common bean cultivars lacking alpha-AI. Common bean seeds appear to contain several factors responsible for the bruchid resistance. PMID:10366733

  12. Characterization, crystallization and preliminary X-ray crystallographic analysis of the complex between barley alpha-amylase and the bifunctional alpha-amylase/subtilisin inhibitor from barley seeds.

    PubMed

    Vallée, F; Kadziola, A; Bourne, Y; Abe, J; Svensson, B; Haser, R

    1994-02-11

    The complex between a member of the barley malt alpha-amylase isozyme 2 family (AMY2-2), and the endogenous bifunctional alpha-amylase/subtilisin inhibitor, BASI, has been crystallized by the hanging drop vapour diffusion technique at a AMY2-2: BASI molar ratio of 1:1. Crystals have been grown within 4 days from solutions containing polyethylene glycol and calcium chloride. Analysis of single crystals by gel electrophoresis showed the presence of both proteins in the crystal lattice. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit cell dimensions a = 74.5 A, b = 96.9 A, c = 171.3 A and they diffract to 2.0 A resolution. The presence of two molecules of the 1:1 complex in the asymmetric unit gives a solvent content of 45% by volume. The 1:1 stoichiometry of the complex was confirmed by the molecular replacement method, using as a search model the recently determined three-dimensional structure of the barley alpha-amylase. PMID:8107117

  13. Screening alpha-glucosidase and alpha-amylase inhibitors from natural compounds by molecular docking in silico.

    PubMed

    Jhong, Chien-Hung; Riyaphan, Jirawat; Lin, Shih-Hung; Chia, Yi-Chen; Weng, Ching-Feng

    2015-01-01

    The alpha-glucosidase inhibitor is a common oral anti-diabetic drug used for controlling carbohydrates normally converted into simple sugars and absorbed by the intestines. However, some adverse clinical effects have been observed. The present study seeks an alternative drug that can regulate the hyperglycemia by down-regulating alpha-glucosidase and alpha-amylase activity by molecular docking approach to screen the hyperglycemia antagonist against alpha-glucosidase and alpha-amylase activities from the 47 natural compounds. The docking data showed that Curcumin, 16-hydroxy-cleroda-3,13-dine-16,15-olide (16-H), Docosanol, Tetracosanol, Antroquinonol, Berberine, Catechin, Quercetin, Actinodaphnine, and Rutin from 47 natural compounds had binding ability towards alpha-amylase and alpha-glucosidase as well. Curcumin had a better biding ability of alpha-amylase than the other natural compounds. Analyzed alpha-glucosidase activity reveals natural compound inhibitors (below 0.5 mM) are Curcumin, Actinodaphnine, 16-H, Quercetin, Berberine, and Catechin when compared to the commercial drug Acarbose (3 mM). A natural compound with alpha-amylase inhibitors (below 0.5 mM) includes Curcumin, Berberine, Docosanol, 16-H, Actinodaphnine/Tetracosanol, Catechin, and Quercetin when compared to Acarbose (1 mM). When taken together, the implication is that molecular docking is a fast and effective way to screen alpha-glucosidase and alpha-amylase inhibitors as lead compounds of natural sources isolated from medicinal plants. PMID:26154585

  14. Molecular characterization of a bean alpha-amylase inhibitor that inhibits the alpha-amylase of the mexican bean weevil Zabrotes subfasciatus.

    PubMed

    Grossi de Sa, M F; Mirkov, T E; Ishimoto, M; Colucci, G; Bateman, K S; Chrispeels, M J

    1997-01-01

    Cultivated varieties of the common bean (Phaseolus vulgaris L.) contain an alpha-amylase inhibitor (alpha AI-1) that inhibits porcine pancreatic alpha-amylase (PPA; EC 3.2.1.1) and the amylases of certain seed weevils, but not that of the Mexican bean weevil, Zabrotes subfasciatus. A variant of alpha AI-1, called alpha AI-2, is found in certain arcelin-containing wild accessions of the common bean. The variant alpha AI-2 inhibits Z. subfasciatus alpha-amylase (ZSA), but not PPA. We purified alpha AI-2 and studied its interaction with ZSA. The formation of the alpha AI-2-ZSA complex is time-dependent and occurs maximally at pH 5.0 or below. When a previously isolated cDNA assumed to encode alpha AI-2 was expressed in transgenic tobacco seeds, the seeds contained inhibitory activity toward ZSA but not toward PPA, confirming that the cDNA encodes alpha AI-2. The inhibitors alpha AI-1 and alpha AI-2 share 78% sequence identity at the amino acid level and they differ in an important region that is part of the site where the enzyme binds the inhibitor. The swap of a tripeptide in this region was not sufficient to change the specificity of the two inhibitors towards their respective enzymes. The three-dimensional structure of the alpha AI-1/PPA complex has just been solved and we recently obtained the derived amino acid sequence of ZSA. This additional information allows us to discuss the results described here in the framework of the amino acid residues of both proteins involved in the formation of the enzyme-inhibitor complex and to pinpoint the amino acids responsible for the specificity of the interaction. PMID:9431678

  15. Effects of alpha-amylase and its inhibitors on acid production from cooked starch by oral streptococci.

    PubMed

    Aizawa, S; Miyasawa-Hori, H; Nakajo, K; Washio, J; Mayanagi, H; Fukumoto, S; Takahashi, N

    2009-01-01

    This study evaluated acid production from cooked starch by Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguinis and Streptococcus mitis, and the effects of alpha-amylase inhibitors (maltotriitol and acarbose) and xylitol on acid production. Streptococcal cell suspensions were anaerobically incubated with various carbohydrates that included cooked potato starch in the presence or absence of alpha-amylase. Subsequently, the fall in pH and the acid production rate at pH 7.0 were measured. In addition, the effects of adding alpha-amylase inhibitors and xylitol to the reaction mixture were evaluated. In the absence of alpha-amylase, both the fall in pH and the acid production rate from cooked starch were small. On the other hand, in the presence of alpha-amylase, the pH fell to 3.9-4.4 and the acid production rate was 0.61-0.92 micromol per optical density unit per min. These values were comparable to those for maltose. When using cooked starch, the fall in pH by S. sanguinis and S. mitis was similar to that by S. mutans and S. sobrinus. For all streptococci, alpha-amylase inhibitors caused a decrease in acid production from cooked starch, although xylitol only decreased acid production by S. mutans and S. sobrinus. These results suggest that cooked starch is potentially acidogenic in the presence of alpha-amylase, which occurs in the oral cavity. In terms of the acidogenic potential of cooked starch, S. sanguinis and S. mitis were comparable to S. mutans and S. sobrinus. Alpha-amylase inhibitors and xylitol might moderate this activity. PMID:19136828

  16. Isolation and activity of an alpha-amylase inhibitor from white kidney beans.

    PubMed

    Zhang, Xiao-qi; Yang, Ming-yan; Ma, Yu; Tian, Jia; Song, Ji-Rong

    2007-12-01

    An alpha-amylase inhibitor (alpha-AI) was isolated from white kidney beans (Phaseolus vulgaris L) by ethanol fractional precipitation, ion exchange chromatography and gel filtration column chromatography. It was a homogeneity glycoprotein demonstrated by SDS-PAGE and gel filtration on CL-6B. The glycoprotein contained 88.2% protein and was rich in aspartic acid, glutamic acid, leucine, threonine and serine. The carbohydrate moiety was consisted of Man, Glc, Gal and Xyl in a mole ratio of 2.42: 1.50: 1.52: 1.00. The glycan and the core protein backbone was connected by O-linkage as determined by beta-elimination reaction. The continuous oral administration of the alpha-AI (150 mg x kg(-1) x d(-1)) for 7 days can lower fasting blood glucose and 300 mg x kg(-1) x d(-1) alpha-AI for 7 days can improve the sugar tolerance on alloxan-dependent diabetic model rats. The result showed the alpha-AI obtained from white kidney beans had good hypoglycemic effect on alloxan induced diabetic rats and may have high potential pharmaceutical value as a regulative digestive-starch degradation in patients suffering from diabetes. PMID:18338641

  17. Protein structures of common bean (Phaseolus vulgaris) alpha-amylase inhibitors.

    PubMed

    Lee, Shih-Chieh; Gepts, Paul L; Whitaker, John R

    2002-10-23

    Two nucleotide sequences for genes that encode alpha-amylase inhibitor 4 (alphaAI-4) from white kidney bean (WKB) cv. 858, designated gene alphaAI-4 (Accession No. ), and alpha-amylase inhibitor 5 (alphaAI-5) from black bean (BB), designated gene alphaAI-5 (Accession No. ), were determined. Genes alphaAI-4 and alphaAI-5 encode 244 amino acid prepro-alphaAI-4 and prepro-alphaAI-5 polypeptides that are 93 and 95% identical with alpha-amylase inhibitor l (alphaAI-l; Hoffman, L. M.; Ma, Y.; Barker, R. F. Nucleic Acids Res. 1982, 10, 7819-7828), 40 and 43% identical with red kidney bean lectin, and 52 and 55% identical with arcelin l of wild-type bean. The high degree of sequence similarity indicates the evolutionary relationship among these genes. PCR analysis of genomic DNA purified from six genotypes of Phaseolus vulgaris showed very similar band patterns in 2% agarose gel, another indication of the conserved size homology among these genes. Proteolytic processing sites were located between Asn77 and Ser78 for pro-alphaAI-4 and pro-alphaAI-5. A bend next to Asn77 in three-dimensional model structures of alphaAI-4 and alphaAI-5 proinhibitors indicates that the proteolytic cleavage is necessary to remove the conformational constraint for activation to the mature protein. Mature WKB alphaAI-4 was composed of four subunits (2alpha2beta) and had a molecular weight of 50000 determined by multiangle laser light scattering and 56714 determined by laser-assisted time-of-flight mass spectrometry. PMID:12381161

  18. Specific inhibition of barley alpha-amylase 2 by barley alpha-amylase/subtilisin inhibitor depends on charge interactions and can be conferred to isozyme 1 by mutation.

    PubMed

    Rodenburg, K W; Vallée, F; Juge, N; Aghajari, N; Guo, X; Haser, R; Svensson, B

    2000-02-01

    alpha-Amylase 2 (AMY2) and alpha-amylase/subtilisin inhibitor (BASI) from barley bind with Ki = 0.22 nM. AMY2 is a (beta/alpha)8-barrel enzyme and the segment Leu116-Phe143 in domain B (Val89-Ile152), protruding at beta-strand 3 of the (beta/alpha)8-barrel, was shown using isozyme hybrids to be crucial for the specificity of the inhibitor for AMY2. In the AMY2-BASI crystal structure [F. Vallée, A. Kadziola, Y. Bourne, M. Juy, K. W. Rodenburg, B. Svensson & R. Haser (1998) Structure 6, 649-659] Arg128AMY2 forms a hydrogen bond with Ser77BASI, while Asp142AMY2 makes a salt-bridge with Lys140BASI. These two enzyme residues are substituted by glutamine and asparagine, respectively, to assess their contribution in binding of the inhibitor. These mutations were performed in the well-expressed, inhibitor-sensitive hybrid barley alpha-amylase 1 (AMY1)-(1-90)/AMY2-(90-403) with Ki = 0.33 nM, because of poor production of AMY2 in yeast. In addition Arg128, only found in AMY2, was introduced into an AMY1 context by the mutation T129R/K130P in the inhibitor-insensitive hybrid AMY1-(1-161)/AMY2-(161-403). The binding energy was reduced by 2.7-3.0 kcal.mol-1 as determined from Ki after the mutations R128Q and D142N. This corresponds to loss of a charged interaction between the protein molecules. In contrast, sensitivity to the inhibitor was gained (Ki = 7 microM) by the mutation T129R/K130P in the insensitive isozyme hybrid. Charge screening raised Ki 14-20-fold for this latter mutant, AMY2, and the sensitive isozyme hybrid, but only twofold for the R128Q and D142N mutants. Thus electrostatic stabilization was effectively introduced and lost in the different mutant enzyme-inhibitor complexes and rational engineering using an inhibitor recognition motif to confer binding to the inhibitor mimicking the natural AMY2-BASI complex. PMID:10672010

  19. Stopped-flow kinetic studies of the reaction of barley alpha-amylase/subtilisin inhibitor and the high pI barley alpha-amylase.

    PubMed

    Sidenius, U; Olsen, K; Svensson, B; Christensen, U

    1995-03-20

    The interaction of alpha-amylase/subtilisin inhibitor (BASI) from barley seeds and the high pI barley alpha-amylase (AMY2) de novo synthesized during seed germination, has been studied at pH 8.0, 25 degrees C, using stopped-flow fluorescence spectroscopy, equilibrium fluorescence titration and kinetic analysis of the displacement of BASI from the BASI-AMY2 complex by the substrate blue starch. The results are in accordance with a two-step reaction model: [formula: see text] The resulting values of the kinetic parameters were: k2/K1 = (1.0 +/- 0.2) x 10(6) M-1.s-1, K1 = 0.4 +/- 0.21 mM, k2 = 320 +/- 150 s-1, k-2 = (7.2 +/- 0.6) x 10(-5)s-1, and the overall dissociation constant Kd = (0.7 +/- 0.1) x 10(-10) M. BASI thus is best characterized as a fast reacting, tight-binding inhibitor of AMY2. PMID:7698332

  20. Activation of bean (Phaseolus vulgaris) alpha-amylase inhibitor requires proteolytic processing of the proprotein.

    PubMed Central

    Pueyo, J J; Hunt, D C; Chrispeels, M J

    1993-01-01

    Seeds of the common bean (Phaseolus vulgaris) contain a plant defense protein that inhibits the alpha-amylases of mammals and insects. This alpha-amylase inhibitor (alpha AI) is synthesized as a proprotein on the endoplasmic reticulum and is proteolytically processed after arrival in the protein storage vacuoles to polypeptides of relative molecular weight (M(r)) 15,000 to 18,000. We report two types of evidence that proteolytic processing is linked to activation of the inhibitory activity. First, by surveying seed extracts of wild accessions of P. vulgaris and other species in the genus Phaseolus, we found that antibodies to alpha AI recognize large (M(r) 30,000-35,000) polypeptides as well as typical alpha AI processing products (M(r) 15,000-18,000). Alpha AI activity was found in all extracts that had the typical alpha AI processed polypeptides, but was absent from seed extracts that lacked such polypeptides. Second, we made a mutant alpha AI in which asparagine-77 is changed to aspartic acid-77. This mutation slows down the proteolytic processing of pro-alpha AI when the gene is expressed in tobacco. When pro-alpha AI was separated from mature alpha AI by gel filtration, pro-alpha AI was found not to have alpha-amylase inhibitory activity. We interpret these results to mean that formation of the active inhibitor is causally related to proteolytic processing of the proprotein. We suggest that the polypeptide cleavage removes a conformational constraint on the precursor to produce the biochemically active molecule. PMID:8310064

  1. Activation of bean (Phaseolus vulgaris) [alpha]-amylase inhibitor requires proteolytic processing of the proprotein

    SciTech Connect

    Pueyo, J.J.; Hunt, D.C.; Chrispeels, M.J. )

    1993-04-01

    Seeds of the common bean (Phaseolus vulgaris) contain a plant defense protein that inhibits the [alpha]-amylases of mammals and insects. This [alpha]-amylase inhibitor ([alpha]Al) is synthesized as a proprotein on the endoplasmic reticulum and is proteolytically processed after arrival in the protein storage vacuoles to polypeptides of relative molecular weight (M[sub r]) 15,000 to 18,000. The authors report two types of evidence that proteolytic processing is linked to activation of the inhibitory activity. First, by surveying seed extracts of wild accessions of P. vulgaris and other species in the genus Phaseolus, they found that antibodies to [alpha]Al recognize large (M[sub r] 30,000-35,000) polypeptides as well as typical [alpha]Al processing products (M[sub r] 15,000-18,000). [alpha]Al activity was found in all extracts that had the typical [alpha]Al processed polypeptides, but was absent from seed extracts that lacked such polypeptides. Second, they made a mutant [alpha]Al in which asparagine-77 is changed to aspartic acid-77. This mutation slows down the proteolytic processing of pro-[alpha]Al when the gene is expressed in tobacco. When pro-[alpha]Al was separated from mature [alpha]Al by gel filtration, pro-[alpha]Al was found not to have [alpha]-amylase inhibitory activity. The authors interpret these results to mean that formation of the active inhibitor is causally related to proteolytic processing of the proprotein. They suggest that the polypeptide cleavage removes a conformation constraint on the precursor to produce the biochemically active molecule. 43 refs., 5 figs., 1 tab.

  2. Complete sequence, subunit structure, and complexes with pancreatic alpha-amylase of an alpha-amylase inhibitor from Phaseolus vulgaris white kidney beans.

    PubMed

    Kasahara, K; Hayashi, K; Arakawa, T; Philo, J S; Wen, J; Hara, S; Yamaguchi, H

    1996-07-01

    The complete amino acid sequence of a white kidney bean (Phaseolus vulgaris) alpha-amylase inhibitor (PHA-I), which is composed of two kinds of glycopolypeptide subunits, alpha and beta, was established by conventional methods. The polypeptide molecular weight of PHA-I determined by the light-scattering technique, considered together with the sequence molecular weights revealed for the subunits, indicated that PHA-I has the subunit stoichiometry of (alpha beta)2 complex. Inhibition test of PHA-I with increasing amounts of porcine pancreatic alpha-amylase (PPA) suggested that an inactive 2:1 complex is formed between PPA and PHA-I. In fact, two complexes differing from each other in the molar ratio of PPA to PHA-I were separated by gel filtration, and molecular weight estimation by the light-scattering technique confirmed that they are complexes of PHA-I with one or two PPA molecules. The binding of PPA to PHA-I appeared to follow simple binomial statistics, suggesting that two binding sites on PHA-I are independent and of high affinity for PPA. PMID:8864861

  3. [Inhibitors of alpha-amylase from plants--a possibility to treat diabetes mellitus type II by phytotherapy?].

    PubMed

    Melzig, Matthias F; Funke, Ines

    2007-01-01

    Antidiabetics of plant origin are in common use. A proof of their effectiveness or their mode of action is often missing. The aim of this work was to review the knowledge about inhibitors of alpha-amylase from plants and to comment on the use in anti-diabetic treatment. Herbal alpha-amylase inhibitors are rarely described in the literature, nevertheless they have the ability to lower postprandial blood glucose level and should be used in the supplementary treatment of diabetes. Important constituents for the inhibitory activity against alpha-amylase are mainly polyphenolic compounds. There is a need for further clinical studies to establish a rational therapy with traditional herbal preparations, especially for the leaves from the blueberry, tamarind, lemon balm and rosemary, the hulls from white kidney beans or green tea extract. PMID:17704980

  4. The relationship between the level of salivary alpha amylase activity and pain severity in patients with symptomatic irreversible pulpitis

    PubMed Central

    Shahriari, Shahriar; Goodarzi, Mohammad Taghi; Moghimbeigi, Abbas; Jazaeri, Mina; Babaei, Parisa

    2013-01-01

    Objectives Assessment of dental pain severity is very challenging in dentistry. Previous studies have suggested that elevated salivary alpha amylase may contribute to increased physical stresses. There is a close association between salivary alpha amylase and plasma norepinephrine under stressful physical conditions. The aim of this study was to evaluate the relationship between pain severity and salivary alpha amylase levels in patients with symptomatic irreversible pulpitis. Materials and Methods Thirty-six patients (20 females and 16 males) with severe tooth pain due to symptomatic irreversible pulpitis were selected. The visual analogue scale (VAS) score was used to assess the pain severity in each patient. Unstimulated whole saliva was collected, and the level of alpha amylase activity was assessed by the spectrophotometric method. Statistical analysis was performed using SPSS 13. Results The level of alpha amylase was significantly increased in the saliva in association with pain severity assessed by VAS. The salivary alpha amylase was also elevated with increased age and in males. Conclusions There was a significant correlation between the VAS pain scale and salivary alpha amylase level, which indicates this biomarker may be a good index for the objective assessment of pain intensity. PMID:24010080

  5. The spectrum of low molecular weight alpha-amylase/protease inhibitor genes expressed in the US bread wheat Butte 86

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The complement of genes encoding alpha-amylase/protease inhibitors expressed in Triticum aestivum cv. Butte 86 was characterized by transcript and proteomic analysis. Coding sequences for 18 distinct proteins were identified among a collection of expressed sequence tags (ESTs) from Butte 86 developi...

  6. Identification of essential amino acid residues of an alpha-amylase inhibitor from Phaseolus vulgaris white kidney beans.

    PubMed

    Takahashi, T; Hiramoto, S; Wato, S; Nishimoto, T; Wada, Y; Nagai, K; Yamaguchi, H

    1999-11-01

    Kidney bean (Phaseolus vulgaris) alpha-amylase inhibitors, which are bivalent inhibitors with the subunit stoichiometry of (alphabeta)(2) complex, have been inferred to contain unique arginine, tryptophan, and tyrosine residues essential for the inhibitory activity. To test the validity of this inference, an attempt was made to identify the essential amino acid residues of a white kidney bean (P. vulgaris) alpha-amylase inhibitor (PHA-I) by using the chemical modification technique combined with amino acid sequencing and mass spectrometry. Exhaustive modification of the arginine residues by phenylglyoxal did not lead to a marked loss of activity, suggesting that no arginine residue is directly associated with the inhibitory activity. N-Bromosuccinimide treatment of PHA-I in the presence or absence of a substrate alpha-amylase revealed the involvement of two tryptophan residues in alpha-amylase inhibition, and they were identified as Trp188 of the beta-subunit by amino acid sequencing and mass spectrometry of lysylendopeptidase peptides. Further, two tyrosine residues were preferentially modified either by N-acetylimidazole or by tetranitromethane, resulting in a concomitant loss of most of the PHA-I activity. Amino acid sequencing of the lysylendopeptidase peptides from a tetranitromethane-modified PHA-I identified Tyr186 of the beta-subunit as an essential residue. PMID:10544275

  7. Porcine pancreatic alpha-amylase inhibition by the kidney bean (Phaseolus vulgaris) inhibitor (alpha-AI1) and structural changes in the alpha-amylase inhibitor complex.

    PubMed

    Santimone, Marius; Koukiekolo, Roger; Moreau, Yann; Le Berre, Véronique; Rougé, Pierre; Marchis-Mouren, Guy; Desseaux, Véronique

    2004-02-12

    Porcine pancreatic alpha-amylase (PPA) is inhibited by the red kidney bean (Phaseolus vulgaris) inhibitor alpha-AI1 [Eur. J. Biochem. 265 (1999) 20]. Inhibition kinetics were carried out using DP 4900-amylose and maltopentaose as substrate. As shown by graphical and statistical analysis of the kinetic data, the inhibitory mode is of the mixed noncompetitive type whatever the substrate thus involving the EI, EI2, ESI and ESI2 complexes. This contrast with the E2I complex obtained in the crystal and with biophysical studies. Such difference very likely depends on the [I]/[E] ratio. At low ratio, the E2I complex is favoured; at high ratio the EI, ESI and EI2 complexes are formed. The inhibition model also differs from those previously proposed for acarbose [Eur. J. Biochem. 241 (1996) 787 and Eur. J. Biochem. 252 (1998) 100]. In particular, with alpha-AI1, the inhibition takes place only when PPA and alpha-AI are preincubated together before adding the substrate. This indicates that the abortive PPA-alphaAI1 complex is formed during the preincubation period. One additional carbohydrate binding site is also demonstrated yielding the ESI complex. Also, a second protein binding site is found in EI2 and ESI2 abortive complexes. Conformational changes undergone by PPA upon alpha-AI1 binding are shown by higher sensitivity to subtilisin attack. From X-ray analysis of the alpha-AI1-PPA complex (E2I), the major interaction occurs with two hairpin loops L1 (residues 29-46) and L2 (residues 171-189) of alpha-AI1 protruding into the V-shaped active site of PPA. The hydrolysis of alpha-AI1 that accounts for the inhibitory activity is reported. PMID:14871659

  8. Protective mechanism of the Mexican bean weevil against high levels of alpha-amylase inhibitor in the common bean.

    PubMed Central

    Ishimoto, M; Chrispeels, M J

    1996-01-01

    Alpha-amylase inhibitor (alpha AI) protects seeds of the common bean (Phaseolus vulgaris) against predation by certain species of bruchids such as the cowpea weevil (Callosobruchus maculatus) and the azuki bean weevil (Callosobruchus chinensis), but not against predation by the bean weevil (Acanthoscelides obtectus) or the Mexican bean weevil (Zabrotes subfasciatus), insects that are common in the Americas. We characterized the interaction of alpha AI-1 present in seeds of the common bean, of a different isoform, alpha AI-2, present in seeds of wild common bean accessions, and of two homologs, alpha AI-Pa present in seeds of the tepary bean (Phaseolus acutifolius) and alpha AI-Pc in seeds of the scarlet runner bean (Phaseolus coccineus), with the midgut extracts of several bruchids. The extract of the Z. subfasciatus larvae rapidly digests and inactivates alpha AI-1 and alpha AI-Pc, but not alpha AI-2 or alpha AI-Pa. The digestion is caused by a serine protease. A single proteolytic cleavage in the beta subunit of alpha AI-1 occurs at the active site of the protein. When degradation is prevented, alpha AI-1 and alpha AI-Pc do not inhibit the alpha-amylase of Z. subfasciatus, although they are effective against the alpha-amylase of C. chinensis. Alpha AI-2 and alpha AI-Pa, on the other hand, do inhibit the alpha-amylase of Z. subfasciatus, suggesting that they are good candidates for genetic engineering to achieve resistance to Z. subfasciatus. PMID:8787024

  9. Soyacystatin N inhibits proteolysis of wheat alpha-amylase inhibitor and potentiates toxicity against cowpea weevil.

    PubMed

    Amirhusin, Bahagiawati; Shade, Richard E; Koiwa, Hisashi; Hasegawa, Paul M; Bressan, Ray A; Murdock, Larry L; Zhu-Salzman, Keyan

    2004-12-01

    Genetic engineering may be used to introduce multiple insect resistance genes with different modes of action into crop plants. We explored the possible interactions of two differing gene products fed in the diet of cowpea weevil, Callosobruchus maculates (F.), a stored grain pest. The soybean cysteine protease inhibitor soyacystatin N (scN) and alpha-amylase inhibitor (alphaAI) from wheat have defensive function against this coleopteran. When artificial seeds containing both scN and alpha(AI) were infested with eggs of C. maculatus, the delays in larval development were longer than was predicted by summing the developmental delays seen when larvae were fed a diet containing the individual proteins, indicating that the effects of scN and alpha(AI) are synergistic. Alpha(AI) was readily hydrolyzed when incubated with insect gut extract. This proteolytic degradation was inhibited by scN, but not by Kunitz inhibitor (a serine protease inhibitor). Thus, degradation of alpha(AI) was due to proteolysis by insect digestive cysteine proteases. These data suggest that C. maculatus uses digestive enzymes not only to function in food protein digestion but also to defend the insects themselves by helping reduce the concentration of a toxic dietary protein. PMID:15666770

  10. Capillary electrophoresis as a screening tool for alpha amylase inhibitors in plant extracts

    PubMed Central

    Hamdan, Imad I.; Afifi, Fatima U.

    2010-01-01

    Capillary electrophoresis (CE) method was developed for screening plant extract for potential alpha amylase (AA) inhibitory activity. The method was validated against a well established UV method. Overall, the proposed method was shown able to detect plants with significant alpha amylase inhibitory activity but not those with rather clinically insignificant activities. Fifty plant species were screened using both the proposed CE method and the UV method and seven plant species were found to possess significant AA inhibitory activities. Two plant species were proved to have alpha amylase inhibitory activity for the first time. PMID:24115900

  11. Kinetics and energetics of the binding between barley alpha-amylase/subtilisin inhibitor and barley alpha-amylase 2 analyzed by surface plasmon resonance and isothermal titration calorimetry.

    PubMed

    Nielsen, Peter K; Bønsager, Birgit C; Berland, Carolyn R; Sigurskjold, Bent W; Svensson, Birte

    2003-02-18

    The kinetics and energetics of the binding between barley alpha-amylase/subtilisin inhibitor (BASI) or BASI mutants and barley alpha-amylase 2 (AMY2) were determined using surface plasmon resonance and isothermal titration calorimetry (ITC). Binding kinetics were in accordance with a 1:1 binding model. At pH 5.5, [Ca(2+)] = 5 mM, and 25 degrees C, the k(on) and k(off) values were 8.3 x 10(+4) M(-1) s(-1) and 26.0 x 10(-4) s(-1), respectively, corresponding to a K(D) of 31 nM. K(D) was dependent on pH, and while k(off) decreased 16-fold upon increasing pH from 5.5 to 8.0, k(on) was barely affected. The crystal structure of AMY2-BASI shows a fully hydrated Ca(2+) at the protein interface, and at pH 6.5 increase of [Ca(2+)] in the 2 microM to 5 mM range raised the affinity 30-fold mainly due to reduced k(off). The K(D) was weakly temperature-dependent in the interval from 5 to 35 degrees C as k(on) and k(off) were only increasing 4- and 12-fold, respectively. A small salt dependence of k(on) and k(off) suggested a minor role for global electrostatic forces in the binding and dissociation steps. Substitution of a positively charged side chain in the mutant K140L within the AMY2 inhibitory site of BASI accordingly did not change k(on), whereas k(off) increased 13-fold. ITC showed that the formation of the AMY2-BASI complex is characterized by a large exothermic heat (Delta H = -69 +/- 7 kJ mol(-1)), a K(D) of 25 nM (27 degrees C, pH 5.5), and an unfavorable change in entropy (-T Delta S = 26 +/- 7 kJ mol(-1)). Calculations based on the thermodynamic data indicated minimal structural changes during complex formation. PMID:12578360

  12. A putative precursor protein in the evolution of the bean alpha-amylase inhibitor.

    PubMed

    Finardi-Filho, F; Mirkov, T E; Chrispeels, M J

    1996-09-01

    Seeds of the common bean Phaseolus vulgaris and the tepary bean (P. acutifolius) contain a family of plant defence proteins that includes phytohaemagglutinin (PHA), arcelin and alpha-amylase inhibitor (alpha AI). These homologous proteins differ by the absence of short loops at the surface of the protein and by the presence of a proteolytic processing site (Asn77) that allows alpha AI to be post-translationally cleaved and activated. We now report the derived amino acid sequence of two amylase inhibitor-like (AIL) proteins that are not proteolytically processed, although they have the typical processing site. One protein is from the common bean, and the other from the tepary bean. On a dendrogram, these proteins are grouped with alpha AIs rather than with the arcelins or lectins. alpha AI differs from AIL primarily by the deletion of a 15-amino-acid segment from the middle of the AIL sequence. When alpha AI is expressed in tobacco, it is proteolytically processed to form an active molecule. However, AIL sequences are not processed. We suggest that the AIL proteins may be an intermediate in the evolution of an active alpha AI. PMID:8987505

  13. Bean [alpha]-Amylase Inhibitor Confers Resistance to the Pea Weevil (Bruchus pisorum) in Transgenic Peas (Pisum sativum L.).

    PubMed Central

    Schroeder, H. E.; Gollasch, S.; Moore, A.; Tabe, L. M.; Craig, S.; Hardie, D. C.; Chrispeels, M. J.; Spencer, D.; Higgins, TJV.

    1995-01-01

    Bruchid larvae cause major losses of grain legume crops through-out the world. Some bruchid species, such as the cowpea weevil and the azuki bean weevil, are pests that damage stored seeds. Others, such as the pea weevil (Bruchus pisorum), attack the crop growing in the field. We transferred the cDNA encoding the [alpha]-amylase inhibitor ([alpha]-AI) found in the seeds of the common bean (Phaseolus vulgaris) into pea (Pisum sativum) using Agrobacterium-mediated transformation. Expression was driven by the promoter of phytohemagglutinin, another bean seed protein. The [alpha]-amylase inhibitor gene was stably expressed in the transgenic pea seeds at least to the T5 seed generation, and [alpha]-AI accumulated in the seeds up to 3% of soluble protein. This level is somewhat higher than that normally found in beans, which contain 1 to 2% [alpha]-AI. In the T5 seed generation the development of pea weevil larvae was blocked at an early stage. Seed damage was minimal and seed yield was not significantly reduced in the transgenic plants. These results confirm the feasibility of protecting other grain legumes such as lentils, mungbean, groundnuts, and chickpeas against a variety of bruchids using the same approach. Although [alpha]-AI also inhibits human [alpha]-amylase, cooked peas should not have a negative impact on human energy metabolism. PMID:12228429

  14. Characterization and functional properties of the alpha-amylase inhibitor (alpha-AI) from kidney bean (Phaseolus vulgaris) seeds.

    PubMed

    Le Berre-Anton, V; Bompard-Gilles, C; Payan, F; Rougé, P

    1997-11-14

    Alpha-amylase inhibitor (alpha-AI) from kidney bean (Phaseolus vulgaris L. cv Tendergreen) seeds has been purified to homogeneity by heat treatment in acidic medium, ammonium sulphate fractionation, chromatofocusing and gel filtration. Two isoforms, alpha-AI1 and alpha-AI1', of 43 kDa have been isolated which differ from each other by their isoelectric points and neutral sugar contents. The major isoform alpha-AI1 inhibited human and porcine pancreatic alpha-amylases (PPA) but was devoid of activity on alpha-amylases of bacterial or fungal origins. As shown on the Lineweaver-Burk plots, the nature of the inhibition is explained by a mixed non-competitive inhibition mechanism. Alpha-AI1 formed a 1:2 stoichiometric complex with PPA which showed an optimum pH of 4.5 at 30 degrees C. Owing to the low optimum pH found for alpha-AI activity, inhibitor-containing diets such as beans or transgenic plants expressing alpha-AI should be devoid of any harmful effect on human health. PMID:9428656

  15. Characterization of. alpha. -amylase-inhibitor, a lectin-like protein in the seeds of Phaseolus vulgaris

    SciTech Connect

    Moreno, J.; Altabella, T.; Chrispeels, M.J. )

    1990-03-01

    The common bean, Phaseolus vulgaris, contains a glycoprotein that inhibits the activity of mammalian and insect {alpha}-amylases but not of plant {alpha}-amylases. It is therefore classified as an antifeedant or seed defense protein. In P. vulgaris cv Greensleeves, {alpha}-amylase inhibitor ({alpha}Al) is present in embryonic axes and cotyledons, but not in other organs of the plant. The protein is synthesized during the same time period that phaseolin and phytohemagglutinin are made and also accumulates in the protein storage vacuoles (protein bodies). All the glycoforms have complex glycans that are resistant to removal by endoglycosidase H, indicating transport of the protein through the Golgi apparatus. The two different polypeptides correspond to the N-terminal and C-terminal halves of a lectin-like protein encoded by an already identified gene or a gene closely related to it. The primary translation product of {alpha}Al is a polypeptide of M{sub r} 28,000. Immunologically cross-reacting glycopolypeptides of M{sub r} 30,000 to 35,000 are present in the endoplasmic reticulum, while the smaller polypeptides (M{sub r} 15,000-19,000) accumulate in protein storage vacuoles (protein bodies). Together these data indicate that {alpha}Al is a typical bean lectin-type protein that is synthesized on the rough endoplasmic reticulum, modified in the Golgi, and transported to the protein storage vacuoles.

  16. Tobacco plants transformed with the bean. alpha. ai gene express an inhibitor of insect. alpha. -amylase in their seeds. [Nicotiana tabacum; Tenebrio molitor

    SciTech Connect

    Altabella, T.; Chrispeels, M.J. )

    1990-06-01

    Bean (Phaseolus vulgaris L.) seeds contain a putative plant defense protein that inhibits insect and mammalian but not plant {alpha}-amylases. We recently presented strong circumstantial evidence that this {alpha}-amylase inhibitor ({alpha}Al) is encoded by an already-identified lectin gene whose product is referred to as lectin-like-protein (LLP). We have now made a chimeric gene consisting of the coding sequence of the lectin gene that encodes LLP and the 5{prime} and 3{prime} flanking sequences of the lectin gene that encodes phytohemagglutinin-L. When this chimeric gene was expressed in transgenic tobacco (Nicotiana tabacum), we observed in the seeds a series of polypeptides (M{sub r} 10,000-18,000) that cross-react with antibodies to the bean {alpha}-amylase inhibitor. Most of these polypeptides bind to a pig pancreas {alpha}-amylase affinity column. An extract of the seeds of the transformed tobacco plants inhibits pig pancreas {alpha}-amylase activity as well as the {alpha}-amylase present in the midgut of Tenebrio molitor. We suggest that introduction of this lectin gene (to be called {alpha}ai) into other leguminous plants may be a strategy to protect the seeds from the seed-eating larvae of Coleoptera.

  17. Mutational analysis of target enzyme recognition of the beta-trefoil fold barley alpha-amylase/subtilisin inhibitor.

    PubMed

    Bønsager, Birgit C; Nielsen, Peter K; Abou Hachem, Maher; Fukuda, Kenji; Praetorius-Ibba, Mette; Svensson, Birte

    2005-04-15

    The barley alpha-amylase/subtilisin inhibitor (BASI) inhibits alpha-amylase 2 (AMY2) with subnanomolar affinity. The contribution of selected side chains of BASI to this high affinity is discerned in this study, and binding to other targets is investigated. Seven BASI residues along the AMY2-BASI interface and four residues in the putative protease-binding loop on the opposite side of the inhibitor were mutated. A total of 15 variants were compared with the wild type by monitoring the alpha-amylase and protease inhibitory activities using Blue Starch and azoalbumin, respectively, and the kinetics of binding to target enzymes by surface plasmon resonance. Generally, the mutations had little effect on k(on), whereas the k(off) values were increased up to 67-fold. The effects on the inhibitory activity, however, were far more pronounced, and the K(i) values of some mutants on the AMY2-binding side increased 2-3 orders of magnitude, whereas mutations on the other side of the inhibitor had virtually no effect. The mutants K140L, D150N, and E168T lost inhibitory activity, revealing the pivotal role of charge interactions for BASI activity on AMY2. A fully hydrated Ca(2+) at the AMY2-BASI interface mediates contacts to the catalytic residues of AMY2. Mutations involving residues contacting the solvent ligands of this Ca(2+) had weaker affinity for AMY2 and reduced sensitivity to the Ca(2+) modulation of the affinity. These results suggest that the Ca(2+) and its solvation sphere are integral components of the AMY2-BASI complex, thus illuminating a novel mode of inhibition and a novel role for calcium in relation to glycoside hydrolases. PMID:15657043

  18. Assessment of the importance of alpha-amylase inhibitor-2 in bruchid resistance of wild common bean.

    PubMed

    Nishizawa, Keito; Teraishi, Masayoshi; Utsumi, Shigeru; Ishimoto, Masao

    2007-02-01

    Both alpha-amylase inhibitor-2 (alphaAI-2) and arcelin have been implicated in resistance of wild common bean (Phaseolus vulgaris L.) to the Mexican bean weevil (Zabrotes subfasciatus Boheman). Near isogenic lines (NILs) for arcelin 1-5 were generated by backcrossing wild common bean accessions with a cultivated variety. Whereas seeds of a wild accession (G12953) containing both alphaAI-2 and arcelin 4 were completely resistant to Z. subfasciatus, those of the corresponding NIL were susceptible to infestation, suggesting that the principal determinant of resistance was lost during backcrossing. Three independent lines of transgenic azuki bean [Vigna angularis (Willd.) Ohwi and Ohashi] expressing alphaAI-2 accumulated high levels of this protein in seeds. The expression of alphaAI-2 in these lines conferred protection against the azuki bean weevil (Callosobruchus chinensis L.), likely through inhibition of larval digestive alpha-amylase. However, although the seed content of alphaAI-2 in these transgenic lines was similar to that in a wild accession of common bean (G12953), it did not confer a level of resistance to Z. subfasciatus similar to that of the wild accession. These results suggest that alphaAI-2 alone does not provide a high level of resistance to Z. subfasciatus. However, alphaAI-2 is an effective insecticidal protein with a spectrum of activity distinct from that of alphaAI-1, and it may prove beneficial in genetic engineering of insect resistance in legumes. PMID:17186215

  19. Cloning and functional expression of the gene encoding an inhibitor against Aspergillus flavus alpha-amylase, a novel seed lectin from Lablab purpureus (Dolichos lablab).

    PubMed

    Kim, Young-Hwa; Woloshuk, Charles P; Cho, Eun Hee; Bae, Jung Myung; Song, Young-Sun; Huh, Gyung Hye

    2007-04-01

    Maize is one of the more important agricultural crops in the world and, under certain conditions, prone to attack from pathogenic fungi. One of these, Aspergillus flavus, produces toxic and carcinogenic metabolites, called aflatoxins, as byproducts of its infection of maize kernels. The alpha-amylase of A. flavus is known to promote aflatoxin production in the endosperm of these infected kernels, and a 36-kDa protein from the Lablab purpureus, denoted AILP, has been shown to inhibit alpha-amylase production and the growth of A. flavus. Here, we report the isolation of six full-length labAI genes encoding AILP and a detailed analysis of the activities of the encoded proteins. Each of the six labAI genes encoded sequences of 274 amino acids, with the deduced amino acid sequences showing approximately 95-99% identity. The sequences are similar to those of lectin members of a legume lectin-arcelin-alpha-amylase inhibitor family reported to function in plant resistance to insect pests. The labAI genes did not show any of the structures characteristic of conserved structures identified in alpha-amylase inhibitors to date. The recombinant proteins of labAI-1 and labAI-2 agglutinated human red blood cells and inhibited A. flavus alpha-amylase in a manner similar to that shown by AILP. These data indicate that labAI genes are a new class of lectin members in legume seeds and that their proteins have both lectin and alpha-amylase inhibitor activity. These results are a valuable contribution to our knowledge of plant-pathogen interactions and will be applicable for developing protocols aimed at controlling A. flavus infection. PMID:17149640

  20. Interaction of wheat monomeric and dimeric protein inhibitors with alpha-amylase from yellow mealworm (Tenebrio molitor L. larva).

    PubMed Central

    Buonocore, V; Gramenzi, F; Pace, W; Petrucci, T; Poerio, E; Silano, V

    1980-01-01

    The highly purified alpha-amylase from Tenebrio molitor L. larva (yellow mealworm) reversibly combines with two closely related homogeneous glycoprotein inhibitors, one dimeric (termed 'inhibitor 0.19') and one monomeric (termed 'inhibitor 0.28'), from wheat flour. As established by means of difference spectroscopy and kinetic studies, molar combining ratios for the amylase--inhibitor-0.19 and amylase-inhibitor-0.28 complexes were 1:1 and 1:2 respectively. Two amylase--inhibitor-0.19 complexes with slightly different retention volumes on Bio-Gel P-300 and only one amylase--inhibitor-0.28 complex were observed. Dissociation constants of the amylase--inhibitor-0.19 and amylase--inhibitor-0.28 complexes were 0.85 nM and 0.13 nM respectively. A strong tendency of both complexes to precipitate under an ultracentrifugal field was observed; the minimum molecular weight calculated for the two complexes under such conditions was approx. 95 000. The two complexes showed difference spectra indicating involvement of structurally related or identical tryptophyl side chains in the binding of inhibitors 0.28 and 0.19 to the amylase. A model summarizing the main features of the inhibition of the insect amylase by the two wheat protein inhibitors is proposed. PMID:6985361

  1. Hypoglycaemic and anorexigenic activities of an alpha-amylase inhibitor from white kidney beans (Phaseolus vulgaris) in Wistar rats.

    PubMed

    Tormo, M A; Gil-Exojo, I; Romero de Tejada, A; Campillo, J E

    2004-11-01

    An inhibitor of alpha-amylase was isolated and purified from an extract of white kidney beans (Phaseolus vulgaris). The acute oral administration of the inhibitor (50 mg/kg body weight) to adult Wistar rats together with a starch load (2 g/kg body weight suspended in NaCl (9 g/l)) reduced the increase in glycaemia over the basal value (NaCl, 222 (SEM 49); inhibitor, 145 (SEM 16) mmol/l x 180 min; P<0.05) without modifying the insulin response. On administering the inhibitor orally (50 mg/kg body weight dissolved in NaCl (9 g/l)) for 21 d to rats fed on a standard diet, a decline was observed in the glycaemia values on day 0 (NaCl, 5.53 (SEM 0.12); inhibitor, 5.25 (SEM 0.16) mmol/l) relative to those obtained on days 10 (NaCl, 5.00 (SEM 0.14); inhibitor, 4.60 (SEM 0.08) mmol/l; P<0.05) and 21 (NaCl, 5.22 (SEM 0.22); inhibitor, 4.50 (SEM 0.12) mmol/l; P<0.01) of treatment, without modifying the plasma concentration of insulin. There was found to be a significant anorexigenic action of the inhibitor; there was reduced food intake (NaCl, 23.07 (SEM 0.31); inhibitor, 19.50 (SEM 0.49) g/d; P<0.01), a reduced weight gain (NaCl, 52 (SEM 3); inhibitor, -1.33 (SEM 8.9) g/21 d; P<0.01), as well as changes in the activity of some intestinal enzymes such as maltase (NaCl, 87 (SEM 7); inhibitor, 127 (SEM 11) U/g proteins; P<0.05). The present study has shown, for the first time, that the prolonged administration of an alpha-amylase inhibitor reduces blood glucose levels and body-weight gain in Wistar rats. PMID:15533267

  2. Post-translational processing of two alpha-amylase inhibitors and an arcelin from the common bean, Phaseolus vulgaris.

    PubMed

    Young, N M; Thibault, P; Watson, D C; Chrispeels, M J

    1999-03-01

    Mass spectrometric methods were used to investigate the proteolytic processing and glycopeptide structures of three seed defensive proteins from Phaseolus vulgaris. The proteins were the alpha-amylase inhibitors alphaAI-1 and alphaAI-2 and arcelin-5, all of which are related to the seed lectins, PHA-E and PHA-L. The mass data showed that the proteolytic cleavage required for activation of the amylase inhibitors is followed by loss of the terminal Asn residue in alphaAI-1, and in all three proteins, seven or more residues were clipped from the C-termini, in the manner of the seed lectins. In most instances, individual glycoforms could be assigned at each Asn site, due to the unique masses of the plant glycopeptides. It was found that alphaAI-1 and alphaAI-2 differed significantly in their glycosylation patterns, despite their high sequence homology. These data complement the previous X-ray studies of the alpha1-amylase inhibitor and arcelin, where many of the C-terminal residues and glycopeptide residues could not be observed. PMID:10100643

  3. cDNA cloning, biochemical characterization and inhibition by plant inhibitors of the alpha-amylases of the Western corn rootworm, Diabrotica virgifera virgifera.

    PubMed

    Titarenko, E; Chrispeels, M J

    2000-10-01

    We report the characterization and cDNA cloning of two alpha-amylase isozymes from larvae of the Western corn rootworm (Diabrotica virgifera virgifera LeConte). Larvae raised on artificial media have very low levels of amylase activity, and much higher levels are found in larvae raised on maize seedlings. At pH 5.7, the optimum pH for enzyme activity, the alpha-amylases are substantially but not completely inhibited by amylase inhibitors from the common bean (Phaseolus vulgaris) and from wheat (Triticum aestivum). Using the reverse transcriptase polymerase chain reaction (RT-PCR), we cloned two cDNAs with 83% amino acid identity that encode alpha-amylase-like polypeptides. Expression of one of the two cDNAs in insect cells with a baculovirus vector shows that this cDNA encodes an active amylase with a mobility that corresponds to that of one of the two isozymes present in larval extracts. The expressed enzyme is substantially inhibited by the same two inhibitors. We also show that expression in Arabidopsis of the cDNA that encodes the amylase inhibitor AI-1 of the common bean results in the accumulation of active inhibitor in the roots, and the results are discussed with reference to the possibility of using amylase inhibitors as a strategy to genetically engineer maize plants that are resistant to Western corn rootworm larvae. PMID:10899464

  4. Arg-27, Arg-127 and Arg-155 in the beta-trefoil protein barley alpha-amylase/subtilisin inhibitor are interface residues in the complex with barley alpha-amylase 2.

    PubMed

    Rodenburg, K W; Várallyay, E; Svendsen, I; Svensson, B

    1995-08-01

    Arginine residues in barley alpha-amylase/subtilisin inhibitor (BASI) involved in binding to barely alpha-amylase 2 (AMY2) were differentially labelled using AMY2 as protectant and phenylglyoxal (PGO) and [14C]PGO as modifying agents. Chymotryptic fragments of labelled BASI were purified by reverse-phase HPLC, and we concluded that the radiolabelled Arg-27, Arg-155 and most likely Arg-127, identified by amino acid, sequence and 14C analyses, are protected by AMY2. While Arg-106 and Arg-107 showed intermediate reactivity and apparently were only partly accessible, Arg-15, Arg-41 and Arg-61 reacted with PGO and were thus exposed in the BASI-AMY2 complex. Patterns of arginine modification by [14C]PGO in free or in AMY2-complexed BASI were consistent with the results of differential labelling. The AMY2-protected arginines in BASI are at a distance from each other, as deduced from crystal structures of different beta-trefoil proteins (Erythrina caffra and soybean trypsin inhibitors, interleukin-1 alpha and -1 beta and WASI, the wheat homologue), suggesting that the BASI-AMY2 complex has multiple contacts at a larger interface. Accordingly, 11-16-residue-long BASI oligopeptides synthesized to include Arg-27, Arg-106/Arg-107 or Arg-127 were unable to suppress the formation of BASI-AMY2 or the effect of an inhibitory monoclonal antibody to BASI. Since Arg-27 is not conserved in rice and wheat ASIs, we further propose that Arg-155 in BASI is the kinetically identified PGO-sensitive group that is essential for inhibition [Abe, Sidenius and Svensson (1993) Biochem. J. 293, 151-155]. PMID:7639717

  5. Purification and characterization of the beta-trefoil fold protein barley alpha-amylase/subtilisin inhibitor overexpressed in Escherichia coli.

    PubMed

    Bønsager, Birgit C; Praetorius-Ibba, Mette; Nielsen, Peter K; Svensson, Birte

    2003-08-01

    Barley alpha-amylase/subtilisin inhibitor (BASI) is a beta-trefoil fold protein related to soybean trypsin inhibitor (Kunitz) and inhibits barley alpha-amylase isozyme 2 (AMY2), which is de novo synthesized in the seed during germination. Recombinant BASI was produced in Escherichia coli in an untagged form (untagged rBASI), in two His(6)-tag forms (His(6)-rBASI and His(6)-Xa-rBASI), and in an intein-CBD-tagged form (rBASI (intein)). The yields per liter culture after purification were (i) 25 mgl(-1) His(6)-rBASI; (ii) 6 mgl(-1) rBASI purified after cleavage of His(6)-Xa-rBASI by Factor Xa; (iii) 3 mgl(-1) untagged rBASI; and (iv) 0.2 mgl(-1) rBASI after a chitin-column and autohydrolysis of the rBASI-intein-CBD. In Pichia pastoris, rBASI was secreted at 0.1 mgl(-1). The recombinant BASI forms and natural seed BASI (sBASI) all had an identical isoelectric point of 7.2 and a mass of 19,879 Da, as determined by mass spectrometry. The fold of rBASI from the different preparations was confirmed by circular dichroism spectroscopy and rBASI (intein), His(6)-rBASI, and sBASI inhibited AMY2 catalyzed starch hydrolysis with K(i) of 0.10, 0.06, and 0.09 nM, respectively. Surface plasmon resonance analysis of the formation of AMY2/rBASI (intein) gave k(on)=1.3x10(5)M(-1)s(-1), k(off)=1.4x10(-4)s(-1), and K(D)=1.1 nM, and of the savinase-His(6)-rBASI complex k(on)=21.0x10(4)M(-1)s(-1), k(off)=53.0x10(-4)s(-1), and K(D)=25.0 nM, in agreement with sBASI values. K(i) was 77 and 65 nM for inhibition of savinase activity by His(6)-rBASI and sBASI, respectively. PMID:12880767

  6. cDNA sequence and deduced primary structure of an alpha-amylase inhibitor from a bruchid-resistant wild common bean.

    PubMed

    Suzuki, K; Ishimoto, M; Kitamura, K

    1994-06-12

    alpha-Amylase inhibitor-2 (alpha AI-2), a seed storage protein present in a bruchid-resistant wild common bean (Phaseolus vulgaris), inhibits the growth of bruchid pests. The authors isolated and determined the sequence of an 852 nucleotide cDNA, designated as alpha ai2, and found it to contain a 720 base open reading frame (ORF). This ORF encodes a 240 amino-acid alpha AI-2 polypeptide 75.8% identical with alpha-amylase inhibitor-1 (alpha AI-1) and 50.6-55.6% with arcelin-1, phytohemagglutinin (PHA)-L and PHA-E of common bean. The high degree of sequence homology suggests that there is an evolutionary relationship among these genes. PMID:8003534

  7. Potential of the bean alpha-amylase inhibitor alpha-AI-1 to inhibit alpha-amylase activity in true bugs(Hemiptera)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    True bugs (Hemiptera) are an important pest complex not controlled by Bt crops. An alternative source of resistance includes inhibitors of digestive enzymes. aAI-1, an a-amylase inhibitor from the common bean, has been shown to inhibit a-amylases of bruchid pests of grain legumes. Here we quantify t...

  8. Interaction between wheat alpha-amylase/trypsin bi-functional inhibitor and mammalian digestive enzymes: Kinetic, equilibrium and structural characterization of binding.

    PubMed

    Cuccioloni, Massimiliano; Mozzicafreddo, Matteo; Ali, Ishtiaq; Bonfili, Laura; Cecarini, Valentina; Eleuteri, Anna Maria; Angeletti, Mauro

    2016-12-15

    Alpha-amylase/trypsin bi-functional inhibitors (ATIs) are non-gluten protein components of wheat and other cereals that can hypersensitise the human gastrointestinal tract, eventually causing enteropathies in predisposed individuals. These inhibitory proteins can act both directly by targeting specific pro-inflammatory receptors, and indirectly by impairing the activity of digestive enzymes, the latter event causing the accumulation of undigested peptides with potential immunogenic properties. Herein, according to a concerted approach based on in vitro and in silico methods we characterized kinetics, equilibrium parameters and modes of binding of the complexes formed between wheat ATI and two representative mammalian digestive enzymes, namely trypsin and alpha-amylase. Interestingly, we demonstrated ATI to target both enzymes with independent binding sites and with moderately high affinity. PMID:27451220

  9. The impact of single nucleotide polymorphism in monomeric alpha-amylase inhibitor genes from wild emmer wheat, primarily from Israel and Golan

    PubMed Central

    2010-01-01

    Background Various enzyme inhibitors act on key insect gut digestive hydrolases, including alpha-amylases and proteinases. Alpha-amylase inhibitors have been widely investigated for their possible use in strengthening a plant's defense against insects that are highly dependent on starch as an energy source. We attempted to unravel the diversity of monomeric alpha-amylase inhibitor genes of Israeli and Golan Heights' wild emmer wheat with different ecological factors (e.g., geography, water, and temperature). Population methods that analyze the nature and frequency of allele diversity within a species and the codon analysis method (comparing patterns of synonymous and non-synonymous changes in protein coding sequences) were used to detect natural selection. Results Three hundred and forty-eight sequences encoding monomeric alpha-amylase inhibitors (WMAI) were obtained from 14 populations of wild emmer wheat. The frequency of SNPs in WMAI genes was 1 out of 16.3 bases, where 28 SNPs were detected in the coding sequence. The results of purifying and the positive selection hypothesis (p < 0.05) showed that the sequences of WMAI were contributed by both natural selection and co-evolution, which ensured conservation of protein function and inhibition against diverse insect amylases. The majority of amino acid substitutions occurred at the C-terminal (positive selection domain), which ensured the stability of WMAI. SNPs in this gene could be classified into several categories associated with water, temperature, and geographic factors, respectively. Conclusions Great diversity at the WMAI locus, both between and within populations, was detected in the populations of wild emmer wheat. It was revealed that WMAI were naturally selected for across populations by a ratio of dN/dS as expected. Ecological factors, singly or in combination, explained a significant proportion of the variations in the SNPs. A sharp genetic divergence over very short geographic distances compared to

  10. [Baking ingredients, especially alpha-amylase, as occupational inhalation allergens in the baking industry].

    PubMed

    Wüthrich, B; Baur, X

    1990-03-31

    Baker's asthma is the most frequent occupational lung disease in Switzerland and West Germany. Cereal flours, and more rarely flour parasites, are implicated as the responsible allergens. Based on an observation of a case of baker's asthma due to monovalent sensitization to alpha-amylase used as additive to flour, 31 bakers with occupational asthma and/or rhinitis were routinely tested by skin tests and serological RAST examinations for allergic sensitivity to flour, alpha-amylase and other bakery additives. 17/31 subjects (55%) reacted positively in scratch tests to a commercial powdered alpha-amylase and 13/20 (65%) to a lecithin preparation. 23/31 (74%) and 19/31 (61%) were RAST positive to wheat and to rye flour respectively. 32% had RAST specific IgE to alpha-amylase (from Aspergillus oryzae), 19.3% to soya bean flour and 16% to malt. 7/12 and 5/12 respectively reacted to trypsin inhibitor and lipoxidase, the main allergens in soya bean. In two patients monosensitization to alpha-amylase was present. In accordance with other reports we recommend that baking additives, especially alpha-amylase, should be tested in allergological diagnosis of occupational diseases in flour processing workers. Full declaration of all additives used in the bakery industry is needed. PMID:2326614

  11. Evolutionary relationships among proteins in the phytohemagglutinin-arcelin-alpha-amylase inhibitor family of the common bean and its relatives.

    PubMed

    Mirkov, T E; Wahlstrom, J M; Hagiwara, K; Finardi-Filho, F; Kjemtrup, S; Chrispeels, M J

    1994-11-01

    The common bean, Phaseolus vulgaris, contains a family of defense proteins that comprises phytohemagglutinin (PHA), arcelin, and alpha-amylase inhibitor (alpha AI). Here we report eight new derived amino acid sequences of genes in this family obtained with either the polymerase chain reaction using genomic DNA, or by screening cDNA libraries made with RNA from developing beans. These new sequences are: two alpha AI sequences and arcelin-4 obtained from a wild accession of P. vulgaris that is resistant to the Mexican bean weevil (Zabrotes subfasciatus) and the bean weevil (Acanthoscelides obtectus); an alpha AI sequence from the related species P. acutifolius (tepary bean); a PHA and an arcelin-like sequence from P. acutifolius; an alpha AI-like sequence from P. maculatus; and a PHA sequence from an arcelin-5 type P. vulgaris. A dendrogram of 16 sequences shows that they fall into the three identified groups: phytohemagglutinins, arcelins and alpha AIs. A comparison of these derived amino acid sequences indicates that one of the four amino acid residues that is conserved in all legume lectins and is required for carbohydrate binding is absent from all the arcelins; two of the four conserved residues needed for carbohydrate binding are missing from all the alpha AIs. Proteolytic processing at an Asn-Ser site is required for the activation of alpha AI, and this site is present in all alpha AI-like sequences; this processing site is also found at the same position in certain arcelins, which are not proteolytically processed. The presence of this site is therefore not sufficient for processing to occur. PMID:7811969

  12. Effects of a high-pressure treatment on the wheat alpha-amylase inhibitor and its relationship to elimination of allergenicity

    NASA Astrophysics Data System (ADS)

    Yamamoto, S.; Takanohashi, K.; Hara, T.; Odani, S.; Suzuki, A.; Nishiumi, T.

    2010-03-01

    In this study, the effects of high-pressure treatment on structure and allergeincity of alpha amylase inhibitor (a-AI) were investigated. The pressure-induced structural changes of α-AI were estimated by fluorescence spectra and by fourth derivative UV-spectroscopy for probed tyrosine residues and by circular dichroism (CD) spectroscopy. The changes in the tertiary structure detected by fluorescence spectra and by fourth derivative UV-spectroscopy under high pressure were indicated at over 300 MPa. Measurements of CD spectroscopy suggested that the effects of a high-pressure treatment on changes in the secondary structure of α-AI were little. From our results, pressure-induced changes of the α-AI structure were not apparent. On the other hands, the IgE-specific binding activities of pressurized α-AI to sera from allergic patients against wheat, which is estimated by observations of dot-blotting, were decreased by high-pressure treatment. It is known that the pressure-induced elimination of allergenicity is related to the tertiary structural changes of allergen molecules. This study are suspected that the epitopes of α-AI do not contain tyrosine residues, and thus the decrease of IgE-specific binding activities is probably caused by the tertiary structural changes of these parts of α-AI.

  13. A heterotetrameric alpha-amylase inhibitor from emmer (Triticum dicoccon Schrank) seeds.

    PubMed

    Capocchi, A; Muccilli, V; Cunsolo, V; Saletti, R; Foti, S; Fontanini, D

    2013-04-01

    Plants have developed a constitutive defense system against pest attacks, which involves the expression of a set of inhibitors acting on heterologous amylases of different origins. Investigating the soluble protein complement of the hulled wheat emmer we have isolated and characterized a heterotetrameric α-amylase inhibitor (ETI). Based on mass spectrometry data, it is an assembly of proteins highly similar to the CM2/CM3/CM16 found in durum wheat. Our data indicate that these proteins can also inhibit exogenous α-amylases in binary assemblies. The calculated dissociation constants (K(i)) for the pancreatic porcine amylase- and human salivary amylase-ETI complexes are similar to those found in durum and soft wheat. Homology modeling of the CM subunits indicate structural similarities with other proteins belonging to the cereal family of trypsin/α-amylase inhibitors; a possible homology modeled structure for a tetrameric assembly of the subunits is proposed. PMID:23320956

  14. A proprietary alpha-amylase inhibitor from white bean (Phaseolus vulgaris): a review of clinical studies on weight loss and glycemic control.

    PubMed

    Barrett, Marilyn L; Udani, Jay K

    2011-01-01

    Obesity, and resultant health hazards which include diabetes, cardiovascular disease and metabolic syndrome, are worldwide medical problems. Control of diet and exercise are cornerstones of the management of excess weight. Foods with a low glycemic index may reduce the risk of diabetes and heart disease as well as their complications. As an alternative to a low glycemic index diet, there is a growing body of research into products that slow the absorption of carbohydrates through the inhibition of enzymes responsible for their digestion. These products include alpha-amylase and glucosidase inhibitors. The common white bean (Phaseolus vulgaris) produces an alpha-amylase inhibitor, which has been characterized and tested in numerous clinical studies. A specific and proprietary product named Phase 2® Carb Controller (Pharmachem Laboratories, Kearny, NJ) has demonstrated the ability to cause weight loss with doses of 500 to 3000 mg per day, in either a single dose or in divided doses. Clinical studies also show that Phase 2 has the ability to reduce the post-prandial spike in blood glucose levels. Experiments conducted incorporating Phase 2 into food and beverage products have found that it can be integrated into various products without losing activity or altering the appearance, texture or taste of the food. There have been no serious side effects reported following consumption of Phase 2. Gastro-intestinal side effects are rare and diminish upon extended use of the product. In summary, Phase 2 has the potential to induce weight loss and reduce spikes in blood sugar caused by carbohydrates through its alpha-amylase inhibiting activity. PMID:21414227

  15. A proprietary alpha-amylase inhibitor from white bean (Phaseolus vulgaris): A review of clinical studies on weight loss and glycemic control

    PubMed Central

    2011-01-01

    Obesity, and resultant health hazards which include diabetes, cardiovascular disease and metabolic syndrome, are worldwide medical problems. Control of diet and exercise are cornerstones of the management of excess weight. Foods with a low glycemic index may reduce the risk of diabetes and heart disease as well as their complications. As an alternative to a low glycemic index diet, there is a growing body of research into products that slow the absorption of carbohydrates through the inhibition of enzymes responsible for their digestion. These products include alpha-amylase and glucosidase inhibitors. The common white bean (Phaseolus vulgaris) produces an alpha-amylase inhibitor, which has been characterized and tested in numerous clinical studies. A specific and proprietary product named Phase 2® Carb Controller (Pharmachem Laboratories, Kearny, NJ) has demonstrated the ability to cause weight loss with doses of 500 to 3000 mg per day, in either a single dose or in divided doses. Clinical studies also show that Phase 2 has the ability to reduce the post-prandial spike in blood glucose levels. Experiments conducted incorporating Phase 2 into food and beverage products have found that it can be integrated into various products without losing activity or altering the appearance, texture or taste of the food. There have been no serious side effects reported following consumption of Phase 2. Gastro-intestinal side effects are rare and diminish upon extended use of the product. In summary, Phase 2 has the potential to induce weight loss and reduce spikes in blood sugar caused by carbohydrates through its alpha-amylase inhibiting activity. PMID:21414227

  16. Gender determines cortisol and alpha-amylase responses to acute physical and psychosocial stress in patients with borderline personality disorder.

    PubMed

    Inoue, Ayako; Oshita, Harumi; Maruyama, Yoshihiro; Tanaka, Yoshihiro; Ishitobi, Yoshinobu; Kawano, Aimi; Ikeda, Rie; Ando, Tomoko; Aizawa, Saeko; Masuda, Koji; Higuma, Haruka; Kanehisa, Masayuki; Ninomiya, Taiga; Akiyoshi, Jotaro

    2015-07-30

    Borderline personality disorder (BPD) is characterized by affective instability, unstable relationships, and identity disturbance. We measured salivary alpha-amylase (sAA) and salivary cortisol levels in all participants during exposure to the Trier Social Stress Test (TSST) and an electric stimulation stress. Seventy-two BPD patients were compared with 377 age- and gender- matched controls. The State and Trait versions of the Spielberger Anxiety Inventory test (STAI-S and STAI-T, respectively), the Profile of Mood State (POMS) tests, and the Beck Depression Inventory (BDI), the Depression and Anxiety Cognition Scale (DACS) were administered to participants before electrical stimulation. Following TSST exposure, salivary cortisol levels significantly decreased in female patients and significantly increased in male patients compared with controls. POMS tension-anxiety, depression-dejection, anger-hostility, fatigue, and confusion scores were significantly increased in BPD patients compared with controls. In contrast, vigor scores were significantly decreased in BPD patients relative to controls. Furthermore, STAI-T and STAI-S anxiety scores and BDI scores were significantly increased in BPD patient compared with controls. DACS scores were significantly increased in BPD patient compared with controls. Different stressors (e.g., psychological or physical) induced different responses in the HPA and SAM systems in female or male BPD patients. PMID:25979467

  17. The amino acid sequence of a 20 kDa bifunctional subtilisin/alpha-amylase inhibitor from bran [correction of brain] of rice (Oryza sativa L.) seeds.

    PubMed

    Ohtsubo, K; Richardson, M

    1992-08-31

    A 20 kDa bifunctional inhibitor of the microbial proteinase, subtilisin, and the alpha-amylase from the larvae of the red flour beetle (Tribolium castaneum) was purified from bran of rice seeds by saline extraction, precipitation with ammonium sulphate, ion-exchange chromatography on DEAE-Cellulose and Toyopearl CM-650, and preparative HPLC on Vydac C18. The complete primary structure was determined by automatic degradation of the intact, reduced and S-alkylated protein, and by manual DABITC/PITC micro-sequencing of peptides obtained from the protein following separate enzymic digestions with trypsin, pepsin, chymotrypsin, elastase and the protease from S. aureus V8. The protein sequence, which contained 176 residues, showed strong homology with similar bifunctional inhibitors previously isolated from wheat and barley which are related to the Kunitz family of proteinase inhibitors from legume seeds. PMID:1511747

  18. The activity of granulocyte alpha-amylase in acute appendicitis.

    PubMed

    Zakrzewska, I; Gajda, R

    1994-01-01

    The activity of alpha-amylase was measured in isolated granulocytes, serum and urine of 35 patients with acute appendicitis. The measurements were performed before operation and on the 7th day after operation. Slightly increased activity of alpha-amylase was found in the serum and urine of 15 patients. On the 7th day after operation the activity of this enzyme reached normal value. The activity of granulocyte alpha-amylase was elevated in 22 patients. In 2 of them the increased activity still maintained on the 7th day after operation. Positive correlation between the serum and granulocyte alpha-amylase activities was found. These observations allow to conclude that granulocytes are the source of increased alpha-amylase activity in the serum of patients with acute appendicitis. PMID:7497089

  19. Salivary alpha-amylase and cortisol responsiveness following electrical stimulation stress in major depressive disorder patients.

    PubMed

    Tanaka, Yoshihiro; Ishitobi, Yoshinobu; Maruyama, Yoshihiro; Kawano, Aimi; Ando, Tomoko; Okamoto, Shizuko; Kanehisa, Masayuki; Higuma, Haruka; Ninomiya, Taiga; Tsuru, Jusen; Hanada, Hiroaki; Kodama, Kensuke; Isogawa, Koichi; Akiyoshi, Jotaro

    2012-03-30

    Major depressive disorder (MDD) is often associated with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis by chronic stress. In comparison, psychosocial stress-induced activation of salivary α-amylase (sAA) functions as a marker of sympathoadrenal medullary system (SAM) activity. However, in contrast to salivary cortisol, sAA has been less extensively studied in MDD patients. The present study measured sAA and salivary cortisol levels in patients with MDD. The authors determined Profile of Mood State (POMS) and State-Trait anxiety Inventory (STAI) scores, Heart Rate Variability (HRV), and sAA and salivary cortisol levels in 88 patients with MDD and 41 healthy volunteers following the application of electrical stimulation stress. Patients with major depressive disorder were 8 points or more on Hamilton Depression Scale (HAM-D) scores. Tension-Anxiety, Depression-Dejection, Anger-Hostility, Fatigue, and Confusion scores in patients with major depressive disorder were significantly increased compared to healthy controls. In contrast, Vigor scores in patients with MDD were significantly decreased compared with healthy controls. There was no difference in heart rate variability measures between MDD patients and healthy controls. The threshold of electrical stimulation applied in MDD patients was lower than that in healthy controls. SAA levels in female MDD patients were significantly elevated relative to controls both before and after electrical stimulation. Finally, there were no differences in salivary cortisol levels between major depressive patients and controls. In the present study only three time points were explored. Furthermore, the increased secretion of sAA before and after stimulation could allude to an increased responsiveness of novel and uncontrollable situations in patients with MDD. These preliminary results suggest that sAA might be a useful biological marker of MDD. PMID:22063648

  20. Effect of chemicals on fungal alpha-amylase activity.

    PubMed

    Ali, F S; Abdel-Moneim, A A

    1989-01-01

    The effect of 8 growth regulators at concentrations of 1,000, 5,000 and 10,000 ppm on the activity of fungal (Aspergillus flavus var. columnaris) alpha-amylase was studied. Indol acetic acid (IAA) and naphthalene acetic acid (NAA) inhibited alpha-amylase activity by 2% and 7% at 1,000 ppm. The other 6 growth regulators, indol butyric acid (IBA), gibberellic acid, cumarin, cycocel (CCC), atonik-G and kylar, did not inhibit but stimulated alpha-amylase activity (0 to 9%) at 1,000 ppm. All growth regulators studied inhibited alpha-amylase activity at 5,000 and 10,000 ppm concentration except kylar. The effect of organic acids and formaldehyde at 0.01, 0.005, and 0.001 M was studied. Acetic acid stimulated alpha-amylase at all concentrations, but formic acid, oxalic acid, lactic acid and citric acid inhibited alpha-amylase activity by 91, 100, 100 and 79%, respectively, at a concentration of 0.01 M, while by 31, 100, 15 and 20%, respectively, at 0.005 M. Formaldehyde induced 7, 3 and 2% inhibition at 0.01, 0.005 and 0.001 M, respectively. At 0.01 M either sorbitol or fructose inhibited alpha-amylase by 8%, Maltose 7%, sucrose 6%, phenol, glucose and galactose each by 5%, ethanol, glycerol, arabinose and sodium benzoate each by 4%, isopropanol and mannitol 1%, but methanol and ammonium citrate dibasic did not inhibit alpha-amylase. The results indicate that CuCl2, SnCl2, AgNO3 and Fe2(SO4)3 were the strongest inhibitors, followed by Cd(C2H3O2), HgCl2, Na2-EDTA, Na2HPO4, and CaCl2 in decreasing order. NaCl, NaBr and Mn SO4 did not inhibit alpha-amylase at concentrations from 10 mM to 0.01 mM. PMID:2515680

  1. Alpha-amylase inhibitor, CS-1036 binds to serum amylase in a concentration-dependent and saturable manner.

    PubMed

    Honda, Tomohiro; Kaneno-Urasaki, Yoko; Ito, Takashi; Kimura, Takako; Matsushima, Nobuko; Okabe, Hiromi; Yamasaki, Atsushi; Izumi, Takashi

    2014-03-01

    (2R,3R,4R)-4-hydroxy-2-(hydroxymethyl)pyrrolidin-3-yl 4-O-(6-deoxy-β-D-glucopyranosyl)-α-D-glucopyranoside (CS-1036), which is an α-amylase inhibitor, exhibited biphasic and sustained elimination with a long t1/2 (18.4-30.0 hours) in rats and monkeys, but exhibited a short t1/2 (3.7-7.9 hours) in humans. To clarify the species differences in the t1/2, the plasma protein binding of CS-1036 was evaluated by ultrafiltration. A concentration-dependent and saturable plasma protein binding of CS-1036 was observed in rats and monkeys with the dissociation rate constant (KD) of 8.95 and 27.2 nM, and maximal binding capacity (Bmax) of 52.8 and 22.1 nM, respectively. By the assessments of the recombinant amylase and immunoprecipitation, the major binding protein of CS-1036 in rats was identified as salivary amylase (KD 5.64 nM). CS-1036 also showed concentration-dependent and saturable binding to human salivary and pancreatic amylase, with similar binding affinity in rats. However, the protein binding of CS-1036 was constant in human plasma (≤10.2%) due to the lower serum amylase level compared with rats and monkeys. From the calculation of the unbound fraction (fu) in plasma based on in vitro KD and Bmax, the dose-dependent increase in fu after oral administration is speculated to lead to a dose-dependent increase in total body clearance and a high area under the curve/dose at lower doses, such as 0.3 mg/kg in rats. PMID:24319124

  2. Novel prediction method of beer foam stability using protein Z, barley dimeric alpha-amylase inhibitor-1 (BDAI-1) and yeast thioredoxin.

    PubMed

    Iimure, Takashi; Takoi, Kiyoshi; Kaneko, Takafumi; Kihara, Makoto; Hayashi, Katsuhiro; Ito, Kazutoshi; Sato, Kazuhiro; Takeda, Kazuyoshi

    2008-09-24

    Foam stability is an important quality trait of beer. Our previous results of two-dimensional gel electrophoresis (2DE) analyses of beer proteins implied a relationship between barley dimeric alpha-amylase inhibitor-1 (BDAI-1) and beer foam stability as judged by the NIBEM-T analyzer. To develop a novel prediction method of beer foam stability under different conditions of barley cultivar and malt modification, multiple linear regression analysis was applied. The spot intensities of major beer proteins on 2DE gel were quantified and used as explanatory variables. The foam stabilities of 25 beer samples each brewed from malt with different malt modification in one of the three cultivars (cultivars A, B, and C) were explained by the spot intensities of BDAI-1 at the 5% significance level ( r = 0.421). Furthermore, two other major protein spots (b0 and b5) were observed on the 2DE gels of Japanese commercial beer samples with different foam stability. Then, multiple regression for foam stability was calculated using these three spot intensities as explanatory variables. As a result, 72.1% of the beer foam stability in 25 beer samples was explained by a novel multiple regression equation calculated using spot b0 and BDAI-1 as positive explanatory variables and spot b5 as a negative variable. To verify the validity of the multiple regression equation and the explanatory variables, the beer foam stability in practical beer samples was analyzed. As a result, 81.5% of the beer foam stability in 10 Japanese commercial beer samples was also explained by using spot b0 and BDAI-1 as positive explanatory variables and spot b5 as a negative variable. Mass spectrometry analyses followed by database searches revealed that protein spots b0 and b5 were identified as protein Z originated from barley and thioredoxin originated from yeast, respectively. These results confirm that BDAI-1 and protein Z are foam-positive factors and identify yeast thioredoxin as a possible novel foam

  3. On the mechanism of alpha-amylase.

    PubMed

    Oudjeriouat, Naïma; Moreau, Yann; Santimone, Marius; Svensson, Birte; Marchis-Mouren, Guy; Desseaux, Véronique

    2003-10-01

    Two inhibitors, acarbose and cyclodextrins (CD), were used to investigate the active site structure and function of barley alpha-amylase isozymes, AMY1 and AMY2. The hydrolysis of DP 4900-amylose, reduced (r) DP18-maltodextrin and maltoheptaose (catalysed by AMY1 and AMY2) was followed in the absence and in the presence of inhibitor. Without inhibitor, the highest activity was obtained with amylose, kcat/Km decreased 103-fold using rDP18-maltodextrin and 10(5) to 10(6)-fold using maltoheptaose as substrate. Acarbose is an uncompetitive inhibitor with inhibition constant (L1i) for amylose and maltodextrin in the micromolar range. Acarbose did not bind to the active site of the enzyme, but to a secondary site to give an abortive ESI complex. Only AMY2 has a second secondary binding site corresponding to an ESI2 complex. In contrast, acarbose is a mixed noncompetitive inhibitor of maltoheptaose hydrolysis. Consequently, in the presence of this oligosaccharide substrate, acarbose bound both to the active site and to a secondary binding site. alpha-CD inhibited the AMY1 and AMY2 catalysed hydrolysis of amylose, but was a very weak inhibitor compared to acarbose.beta- and gamma-CD are not inhibitors. These results are different from those obtained previously with PPA. However in AMY1, as already shown for amylases of animal and bacterial origin, in addition to the active site, one secondary carbohydrate binding site (s1) was necessary for activity whereas two secondary sites (s1 and s2) were required for the AMY2 activity. The first secondary site in both AMY1 and AMY2 was only functional when substrate was bound in the active site. This appears to be a general feature of the alpha-amylase family. PMID:14511369

  4. Salivary alpha-amylase and cortisol responsiveness following electrical stimulation stress in obsessive-compulsive disorder patients.

    PubMed

    Kawano, Aimi; Tanaka, Yoshihiro; Ishitobi, Yoshinobu; Maruyama, Yoshihiro; Ando, Tomoko; Inoue, Ayako; Okamoto, Shizuko; Imanaga, Junko; Kanehisa, Masayuki; Higuma, Haruka; Ninomiya, Taiga; Tsuru, Jusen; Akiyoshi, Jotaro

    2013-08-30

    Salivary α-amylase (sAA) serves as a marker of sympathoadrenal medullary system (SAM) activity. Salivary AA has not been extensively studied in obsessive-compulsive disorder (OCD) patients. In the current study, 45 OCD patients and 75 healthy volunteers were assessed with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the Profile of Mood State (POMS), and the State-Trait Anxiety Inventory (STAI). Measures of heart rate variability (HRV), sAA, and salivary cortisol were also obtained following the application of electrical stimulation stress. The Y-BOCS and POMS Tension-Anxiety, Depression-Dejection, Anger-Hostility, Fatigue, and Confusion scores were significantly increased in patients with OCD compared with healthy controls. In contrast, Vigor scores were significantly decreased in patients with OCD relative to scores in healthy controls. There was no difference in HRV between the patients and the controls. Salivary AA levels in female and male OCD patients were significantly elevated relative to controls both before and after electrical stimulation. In contrast, there were no differences in salivary cortisol levels between OCD patients and controls. The elevated secretion of sAA before and after stimulation may suggest an increased responsiveness to novel and uncontrollable situations in patients with OCD. An increase in sAA might be a characteristic change of OCD. PMID:23266021

  5. Different polyphenolic components of soft fruits inhibit alpha-amylase and alpha-glucosidase.

    PubMed

    McDougall, Gordon J; Shpiro, Faina; Dobson, Patricia; Smith, Pauline; Blake, Alison; Stewart, Derek

    2005-04-01

    Polyphenol-rich extracts from soft fruits were tested for their ability to inhibit alpha-amylase and alpha-glucosidase. All extracts tested caused some inhibition of alpha-amylase, but there was a 10-fold difference between the least and most effective extracts. Strawberry and raspberry extracts were more effective alpha-amylase inhibitors than blueberry, blackcurrant, or red cabbage. Conversely, alpha-glucosidase was more readily inhibited by blueberry and blackcurrant extracts. The extent of inhibition of alpha-glucosidase was related to their anthocyanin content. For example, blueberry and blackcurrant extracts, which have the highest anthocyanin content, were the most effective inhibitors of alpha-glucosidase. The extracts most effective in inhibiting alpha-amylase (strawberry and raspberry) contain appreciable amounts of soluble tannins. Other tannin-rich extracts (red grape, red wine, and green tea) were also effective inhibitors of alpha-amylase. Indeed, removing tannins from strawberry extracts with gelatin also removed inhibition. Fractionation of raspberry extracts on Sephadex LH-20 produced an unbound fraction enriched in anthocyanins and a bound fraction enriched in tannin-like polyphenols. The unbound anthocyanin-enriched fraction was more effective against alpha-glucosidase than the original extract, whereas the alpha-amylase inhibitors were concentrated in the bound fraction. The LH-20 bound sample was separated by preparative HPLC, and fractions were assayed for inhibition of alpha-amylase. The inhibitory components were identified as ellagitannins using LC-MS-MS. This study suggests that different polyphenolic components of fruits may influence different steps in starch digestion in a synergistic manner. PMID:15796622

  6. [Microbial alpha-amylases: physicochemical properties, substrate specificity and domain structure].

    PubMed

    Avdiiuk, K V; Varbanets', L D

    2013-01-01

    The current literature data on producers, physico-chemical properties and substrate specificity of a-amylases produced by microbes from different taxonomic groups such as bacteria, fungi and yeasts are discussed in the survey. Synthesis of alpha-amylase majority is an inducible process which is stimulated in the presence of starch or products of its hydrolysis. It is possible to increase enzymes activity level by optimization of cultivation conditions of strains-producers. alpha-Amylases, isolated from different sources are distinguished in their physico-chemical properties, particularly in their molecular weights, pH- and thermooptimums, inhibitors and activators. The enzymes hydrolyse soluble starch, amylose, amylopectin, glycogen, maltodextrins, alpha- and beta3-cyclodextrins and other carbohydrate substrates. It is well known that alpha-amylases belong to GH-13 family of glycosyl-hydrolases, which contain the catalytic domain A as (beta/alpha)8-barrel. In addition to domain A, alpha-amylases contain two other domains: B and C, which are localized approximately on opposite sides of (beta/alpha)8-barrel. Most of the known alpha-amylases contain calcium ion, which is located on the surface between domains A and B and plays an important role in stability and activity of the enzyme. PMID:24319968

  7. Inhibition of growth of Aspergillus flavus and fungal alpha-amylases by a lectin-like protein from Lablab purpureus.

    PubMed

    Fakhoury, A M; Woloshuk, C P

    2001-08-01

    Aspergillus flavus is a fungal pathogen of maize causing an important ear rot disease when plants are exposed to drought and heat stress. Associated with the disease is the production of aflatoxins, which are a series of structurally related mycotoxins known to be carcinogenic. Previous research has suggested that the alpha-amylase of A. flavus promotes aflatoxin production in the endosperm of infected maize kernels. We report here the isolation and characterization of a 36-kDa alpha-amylase inhibitor from Lablab purpureus (AILP). AILP inhibited the alpha-amylases from several fungi but had little effect on those from animal and plant sources. The protein inhibited conidial germination and hyphal growth of A. flavus. The amino acid sequence indicated that AILP is similar to lectin members of a lectin-arcelin-alpha-amylase inhibitor family described in common bean and shown to be a component of plant resistance to insect pests. AILP also agglutinated papain-treated red blood cells from human and rabbit. These data indicate that AILP represents a novel variant in the lectin-arcelin-alpha-amylase inhibitor family of proteins having lectin-like and alpha-amylase inhibitory activity. PMID:11497467

  8. Oligosaccharide binding to barley alpha-amylase 1.

    PubMed

    Robert, Xavier; Haser, Richard; Mori, Haruhide; Svensson, Birte; Aghajari, Nushin

    2005-09-23

    Enzymatic subsite mapping earlier predicted 10 binding subsites in the active site substrate binding cleft of barley alpha-amylase isozymes. The three-dimensional structures of the oligosaccharide complexes with barley alpha-amylase isozyme 1 (AMY1) described here give for the first time a thorough insight into the substrate binding by describing residues defining 9 subsites, namely -7 through +2. These structures support that the pseudotetrasaccharide inhibitor acarbose is hydrolyzed by the active enzymes. Moreover, sugar binding was observed to the starch granule-binding site previously determined in barley alpha-amylase isozyme 2 (AMY2), and the sugar binding modes are compared between the two isozymes. The "sugar tongs" surface binding site discovered in the AMY1-thio-DP4 complex is confirmed in the present work. A site that putatively serves as an entrance for the substrate to the active site was proposed at the glycone part of the binding cleft, and the crystal structures of the catalytic nucleophile mutant (AMY1D180A) complexed with acarbose and maltoheptaose, respectively, suggest an additional role for the nucleophile in the stabilization of the Michaelis complex. Furthermore, probable roles are outlined for the surface binding sites. Our data support a model in which the two surface sites in AMY1 can interact with amylose chains in their naturally folded form. Because of the specificities of these two sites, they may locate/orient the enzyme in order to facilitate access to the active site for polysaccharide chains. Moreover, the sugar tongs surface site could also perform the unraveling of amylose chains, with the aid of Tyr-380 acting as "molecular tweezers." PMID:16030022

  9. Production of alpha-amylase by yeast

    SciTech Connect

    Thomse, K.K.

    1987-01-01

    The enzyme alpha-amylase confers to an organism the enzymatic activity for the degradation of polyglucosides with alpha-1,4 glycosidic bonds such as starch and glycogen which are among the major storage compounds in plants and animals. Most alpha-amylases are single polypeptides of molecular weights around 50,000 dalton. They are generally found in the digestive tract of animals and in germinating seeds. Among the products released upon enzymatic degradation of polyglucosides maltose, a sugar that can be utilized as carbon source by yeast, is a major constituent. A cDNA segment complementary to mouse salivary amylase messenger RNA has been inserted into the yeast expression vector pMA56 behind the promoter of the gene encoding alcohol dehydrogenase I of yeast. Yeast transformants harboring plasmids with the normal orientation of the promoter and the mouse amylase cDNA gene produce amylase and release the enzyme in free form into the culture medium. Approximately 90% of the amylase activity is found in the medium. Yeast strains carrying MAL allele and transformed with a plasmid which directed the synthesis of mouse alpha-amylase were tested on plates containing starch and in batch fermentations using different high molecular weight sugars and oligosaccharides as carbon source. The results of these experiments will be discussed. (Refs. 21).

  10. Intracellular alpha-amylase of Streptococcus mutans.

    PubMed

    Simpson, C L; Russell, R R

    1998-09-01

    Sequencing upstream of the Streptococcus mutans gene for a CcpA gene homolog, regM, revealed an open reading frame, named amy, with homology to genes encoding alpha-amylases. The deduced amino acid sequence showed a strong similarity (60% amino acid identity) to the intracellular alpha-amylase of Streptococcus bovis and, in common with this enzyme, lacked a signal sequence. Amylase activity was found only in S. mutans cell extracts, with no activity detected in culture supernatants. Inactivation of amy by insertion of an antibiotic resistance marker confirmed that S. mutans has a single alpha-amylase activity. The amylase activity was induced by maltose but not by starch, and no acid was produced from starch. S. mutans can, however, transport limit dextrins and maltooligosaccharides generated by salivary amylase, but inactivation of amy did not affect growth on these substrates or acid production. The amylase digested the glycogen-like intracellular polysaccharide (IPS) purified from S. mutans, but the amy mutant was able to digest and produce acid from IPS; thus, amylase does not appear to be essential for IPS breakdown. However, when grown on excess maltose, the amy mutant produced nearly threefold the amount of IPS produced by the parent strain. The role of Amy has not been established, but Amy appears to be important in the accumulation of IPS in S. mutans grown on maltose. PMID:9721315

  11. alpha-Amylase inhibitory activity of some Malaysian plants used to treat diabetes; with particular reference to Phyllanthus amarus.

    PubMed

    Ali, Hasenah; Houghton, P J; Soumyanath, Amala

    2006-10-11

    Extracts of six selected Malaysian plants with a reputation of usefulness in treating diabetes were examined for alpha-amylase inhibition using an in vitro model. Inhibitory activity studied by two different protocols (with and without pre-incubation) showed that Phyllanthus amarus hexane extract had alpha-amylase inhibitory properties. Hexane and dichloromethane extracts of Anacardium occidentale, Lagerstroemia speciosa, Averrhoa bilimbiPithecellobium jiringa and Parkia speciosa were not active when tested without pre-incubation. Extraction and fractionation of Phyllanthus amarus hexane extract led to the isolation of dotriacontanyl docosanoate, triacontanol and a mixture of oleanolic acid and ursolic acid. Dotriacontanyl docosanoate and the mixture of oleanolic acid and ursolic acid are reported from this plant species for the first time. All compounds were tested in the alpha-amylase inhibition assay and the results revealed that the oleanolic acid and ursolic acid (2:1) mixture was a potent alpha-amylase inhibitor with IC(50)=2.01 microg/ml (4.41 microM) and that it contributes significantly to the alpha-amylase inhibition activity of the extract. Three pure pentacyclic triterpenoids, oleanolic acid, ursolic acid and lupeol were shown to inhibit alpha-amylase. PMID:16678367

  12. Method for using a yeast alpha-amylase promoter

    DOEpatents

    Gao, Johnway; Skeen, Rodney S.; Hooker, Brian S.; Anderson, Daniel B.

    2003-04-22

    The present invention provides the promoter clone discovery of an alpha-amylase gene of a starch utilizing yeast strain Schwanniomyces castellii. The isolated alpha-amylase promoter is an inducible promoter, which can regulate strong gene expression in starch culture medium.

  13. Structure-based protein engineering for alpha-amylase inhibitory activity of plant defensin.

    PubMed

    Lin, Ku-Feng; Lee, Tian-Ren; Tsai, Ping-Hsing; Hsu, Ming-Pin; Chen, Ching-San; Lyu, Ping-Chiang

    2007-08-01

    The structure of a novel plant defensin isolated from the seeds of the mung bean, Vigna radiate, has been determined by (1)H nuclear magnetic resonance spectroscopy. The three-dimensional structure of VrD2, the V. radiate plant defensin 2 protein, comprises an alpha-helix and one triple-stranded anti-parallel beta-sheet stabilized by four disulfide bonds. This protein exhibits neither insecticidal activity nor alpha-amylase inhibitory activity in spite of showing a similar global fold to that of VrD1, an insecticidal plant defensin that has been suggested to function by inhibiting insect alpha-amylase. Our previous study proposed that loop L3 of plant defensins is important for this inhibition. Structural analyses and surface charge comparisons of VrD1 and VrD2 revealed that the charged residues of L3 correlate with the observed difference in inhibitory activities of these proteins. A VrD2 chimera that was produced by transferring the proposed functional loop of VrD1 onto the structurally equivalent loop of VrD2 supported this hypothesis. The VrD2 chimera, which differs by only five residues compared with VrD2, showed obvious activity against Tenebrio molitor alpha-amylase. These results clarify the mode of alpha-amylase inhibition of plant defensins and also represent a possible approach for engineering novel alpha-amylase inhibitors. Plant defensins are important constituents of the innate immune system of plants, and thus the application of protein engineering to this protein family may provide an efficient method for protecting against crop losses. PMID:17444520

  14. Classification and evolution of alpha-amylase genes in plants.

    PubMed

    Huang, N; Stebbins, G L; Rodriguez, R L

    1992-08-15

    The DNA sequences for 17 plant genes for alpha-amylase (EC 3.2.1.1) were analyzed to determine their phylogenetic relationship. A phylogeny for these genes was obtained using two separate approaches, one based on molecular clock assumptions and the other based on a comparison of sequence polymorphisms (i.e., small and localized insertions) in the alpha-amylase genes. These polymorphisms are called "alpha-amylase signatures" because they are diagnostic of the gene subfamily to which a particular alpha-amylase gene belongs. Results indicate that the cereal alpha-amylase genes fall into two major classes: AmyA and AmyB. The AmyA class is subdivided into the Amy1 and Amy2 subfamilies previously used to classify alpha-amylase genes in barley and wheat. The AmyB class includes the Amy3 subfamily to which most of the alpha-amylase genes of rice belong. Using polymerase chain reaction and oligonucleotide primers that flank one of the two signature regions, we show that the AmyA and AmyB gene classes are present in approximately equal amounts in all grass species examined except barley. The AmyB (Amy3 subfamily) genes in the latter case are comparatively underrepresented. Additional evidence suggests that the AmyA genes appeared recently and may be confined to the grass family. PMID:1502164

  15. Characterization of salivary alpha-amylase binding to Streptococcus sanguis

    SciTech Connect

    Scannapieco, F.A.; Bergey, E.J.; Reddy, M.S.; Levine, M.J. )

    1989-09-01

    The purpose of this study was to identify the major salivary components which interact with oral bacteria and to determine the mechanism(s) responsible for their binding to the bacterial surface. Strains of Streptococcus sanguis, Streptococcus mitis, Streptococcus mutans, and Actinomyces viscosus were incubated for 2 h in freshly collected human submandibular-sublingual saliva (HSMSL) or parotid saliva (HPS), and bound salivary components were eluted with 2% sodium dodecyl sulfate. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western transfer, alpha-amylase was the prominent salivary component eluted from S. sanguis. Studies with {sup 125}I-labeled HSMSL or {sup 125}I-labeled HPS also demonstrated a component with an electrophoretic mobility identical to that of alpha-amylase which bound to S. sanguis. Purified alpha-amylase from human parotid saliva was radiolabeled and found to bind to strains of S. sanguis genotypes 1 and 3 and S. mitis genotype 2, but not to strains of other species of oral bacteria. Binding of ({sup 125}I)alpha-amylase to streptococci was saturable, calcium independent, and inhibitable by excess unlabeled alpha-amylases from a variety of sources, but not by secretory immunoglobulin A and the proline-rich glycoprotein from HPS. Reduced and alkylated alpha-amylase lost enzymatic and bacterial binding activities. Binding was inhibited by incubation with maltotriose, maltooligosaccharides, limit dextrins, and starch.

  16. Alpha-amylase gene transcription in tissues of normal dog.

    PubMed

    Mocharla, H; Mocharla, R; Hodes, M E

    1990-02-25

    We studied the distribution of alpha-amylase mRNA in normal dog tissues by northern blotting (NB) and reverse transcription-polymerase chain reaction (RT-PCR) with human pancreatic (AMY2) and salivary (AMY1) alpha-amylase cDNA-specific primers. Analysis of poly(A+) RNA from various normal tissues by NB indicated the presence of detectable levels of alpha-amylase mRNA transcripts only in pancreas. Dot-blot analysis of DNA amplified with primers common to both (human) isoamylase mRNAs showed presence of alpha-amylase gene transcripts not only in pancreas but also in liver, small intestine, large intestine and fallopian tube. Traces of amylase gene transcripts were also observed in ovary, uterus and lung. Interestingly, amylase transcripts were not detectable in the parotid gland by NB or RT-PCR. We have also localized alpha-amylase mRNA transcripts to dog pancreas by in situ transcription and in situ hybridization. Our results suggest that there is high degree of homology between the alpha-amylase mRNA sequences in dog and human at least in the exon 3-4 regions of the human gene. PMID:2315015

  17. Characterization of salivary alpha-amylase binding to Streptococcus sanguis.

    PubMed Central

    Scannapieco, F A; Bergey, E J; Reddy, M S; Levine, M J

    1989-01-01

    The purpose of this study was to identify the major salivary components which interact with oral bacteria and to determine the mechanism(s) responsible for their binding to the bacterial surface. Strains of Streptococcus sanguis, Streptococcus mitis, Streptococcus mutans, and Actinomyces viscosus were incubated for 2 h in freshly collected human submandibular-sublingual saliva (HSMSL) or parotid saliva (HPS), and bound salivary components were eluted with 2% sodium dodecyl sulfate. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western transfer, alpha-amylase (EC 3.2.1.1) was the prominent salivary component eluted from S. sanguis. Studies with 125I-labeled HSMSL or 125I-labeled HPS also demonstrated a component with an electrophoretic mobility identical to that of alpha-amylase which bound to S. sanguis. Purified alpha-amylase from human parotid saliva was radiolabeled and found to bind to strains of S. sanguis genotypes 1 and 3 and S. mitis genotype 2, but not to strains of other species of oral bacteria. Binding of [125I]alpha-amylase to streptococci was saturable, calcium independent, and inhibitable by excess unlabeled alpha-amylases from a variety of sources, but not by secretory immunoglobulin A and the proline-rich glycoprotein from HPS. Reduced and alkylated alpha-amylase lost enzymatic and bacterial binding activities. Binding was inhibited by incubation with maltotriose, maltooligosaccharides, limit dextrins, and starch. Images PMID:2788139

  18. Some studies of alpha-amylase production using Aspergillus oryzae.

    PubMed

    Esfahanibolandbalaie, Z; Rostami, K; Mirdamadi, S S

    2008-11-15

    The extracellular alpha-amylase production by Aspergillus oryzae was studied in submerged fermentation using an Adlof-Kuhner orbital shaker. The effect of initial pH values in the range of 4 to 7.5 on enzyme production was investigated and initial pH medium of 6.2 +/- 0.1 resulted in enhanced alpha-amylase production. The effect of carbon and nitrogen source and composition was examined and it has been observed that corn starch concentration of 15 g L(-1) has sound effect on enzyme production. The medium containing corn starch, sodium nitrate resulted in considerable higher enzyme production. Further, the yeast extract of 2.5 g L(-1) in the medium produced higher enzyme in view to other organic nitrogen sources. The effect of temperature on alpha-amylase production from 20 to 40 degrees C has been studied and at 35 +/- 1 degrees C higher alpha-amylase has been obtained. The effect of shaker's speed on alpha-amylase production from 50 to 200 rpm was investigated. And at about 180 rpm higher enzyme production has been observed. In the present study, it has been found that glucose has repressing effect on a-amylase production using A. oryzae PTCC5164. PMID:19260332

  19. Alcoholysis reactions from starch with alpha-amylases.

    PubMed

    Santamaría, R I; Del Río, G; Saab, G; Rodríguez, M E; Soberón, X; López-Manguía, A

    1999-06-11

    The ability of alpha-amylases from different sources to carry out reactions of alcoholysis was studied using methanol as substrate. It was found that while the enzymes from Aspergillus niger and Aspergillus oryzae, two well-studied saccharifying amylases, are capable of alcoholysis reactions, the classical bacterial liquefying alpha-amylases from Bacillus licheniformis and Bacillus stearothermophilus are not. The effect of starch and methanol concentration, temperature and pH on the synthesis of glucosides with alpha-amylase from A. niger was studied. Although methanol may inactivate alpha-amylase, a 90% substrate relative conversion can be obtained in 20% methanol at a high starch concentration (15% w/v) due to a stabilizing effect of starch on the enzyme. As the products of alcoholysis are a series of methyl-oligosaccharides, from methyl-glucoside to methyl-hexomaltoside, alcoholysis was indirectly quantified by high performance liquid chromatography analysis of the total methyl-glucoside produced after the addition of glucoamylase to the alpha-amylase reaction products. More alcoholysis was obtained from intact soluble starch than with maltodextrins or pre-hydrolyzed starch. The biotechnological implications of using starch as substrate for the production of alkyl-glucosides is analyzed in the context of these results. PMID:10386619

  20. Salivary Cortisol, Salivary Alpha Amylase, and the Dental Anxiety Scale

    PubMed Central

    Sadi, Hana; Finkelman, Matthew; Rosenberg, Morton

    2013-01-01

    The aim of this study was to investigate the correlation between dental anxiety, salivary cortisol, and salivary alpha amylase (sAA) levels. Furthermore, the aim was to look into individual differences such as age, race, gender, any existing pain, or traumatic dental experience and their effect on dental anxiety. This study followed a cross-sectional design and included a convenience sample of 46. Every patient was asked to complete the Dental Anxiety Scale (DAS) and a basic demographic/dental history questionnaire. A saliva sample, utilizing the method of passive drooling, was then collected in 2-mL cryovials. Samples were analyzed for salivary cortisol and sAA levels by Salimetrics. Significant associations were observed between DAS scores and presence of pain and history of traumatic dental experience. However, no significant correlations were observed between DAS, cortisol, and sAA levels. Our study reconfirms that dental anxiety is associated with presence of pain and a history of traumatic dental experience. On the other hand, our study was the first to our knowledge to test the correlation between the DAS and sAA; nevertheless, our results failed to show any significant correlation between dental anxiety, cortisol, and sAA levels. PMID:23763559

  1. Alpha-amylase Inhibition and Antioxidant Activity of Marine Green Algae and its Possible Role in Diabetes Management

    PubMed Central

    Unnikrishnan, P. S.; Suthindhiran, K.; Jayasri, M. A.

    2015-01-01

    Aim: In the continuing search for safe and efficient antidiabetic drug, marine algae become important source which provide several compounds of immense therapeutic potential. Alpha-amylase, alpha-glucosidase inhibitors, and antioxidant compounds are known to manage diabetes and have received much attention recently. In the present study, four green algae (Chaetomorpha aerea, Enteromorpha intestinalis, Chlorodesmis, and Cladophora rupestris) were chosen to evaluate alpha-amylase, alpha-glucosidase inhibitory, and antioxidant activity in vitro. Materials and Methods: The phytochemical constituents of all the extracts were qualitatively determined. Antidiabetic activity was evaluated by inhibitory potential of extracts against alpha-amylase and alpha-glucosidase by spectrophotometric assays. Antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl, hydrogen peroxide (H2O2), and nitric oxide scavenging assay. Gas chromatography-mass spectrometry (GC-MS) analysis was carried out to determine the major compound responsible for its antidiabetic action. Results: Among the various extracts screened, chloroform extract of C. aerea (IC50 − 408.9 μg/ml) and methanol extract of Chlorodesmis (IC50 − 147.6 μg/ml) showed effective inhibition against alpha-amylase. The extracts were also evaluated for alpha-glucosidase inhibition, and no observed activity was found. Methanol extract of C. rupestris showed notable free radical scavenging activity (IC50 – 666.3 μg/ml), followed by H2O2 (34%) and nitric oxide (49%). Further, chemical profiling by GC-MS revealed the presence of major bioactive compounds. Phenol, 2,4-bis (1,1-dimethylethyl) and z, z-6,28-heptatriactontadien-2-one were predominantly found in the methanol extract of C. rupestris and chloroform extract of C. aerea. Conclusion: Our results demonstrate that the selected algae exhibit notable alpha-amylase inhibition and antioxidant activity. Therefore, characterization of active compounds and its in vivo

  2. Optimization of alpha-amylase application in raw sugar manufacture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In recent years there have been warnings by some U.S. refineries that there may be a penalty for high starch concentration sin raw sugar if starch control is not improved. Most commercial alpha-amylases used by the U.S. sugar industry to control starch have intermediate temperature stability (up to...

  3. Genetics of alpha-amylases in hexaploid oat species.

    PubMed

    Sharopova, N R; Portyanko, V A; Sozinov, A A

    1998-06-01

    The inheritance of alpha-amylases was studied in six F2 populations of hexaploid oats (Avena sativa, A. byzantina, A. fatua, A. sterillis) using polyacrylamide gel electrophoresis. A total of 22 loci was identified and described. Three main linkages of four or five loci each and an additional two pairs of linked loci were detected. It seems likely that the three main linkage groups represent homeologous chromosomes. Matching of alpha-amylase profiles of hexaploid (AACCDD), tetraploid (AACC), and diploid (AA) species was made to assign the linkage groups to particular subgenomes in the hexaploid oat. It was proposed that Linkage 1 (Amy12-Amy10-1-Amy4-Amy13-Amy11) belongs to the D-subgenome; Linkage 2 (Amy10-2, Amy9-Amy8-Amy6) belongs to the A-subgenome; and Linkage 3 (Amy7-Amy3-Amy5-Amy2) belongs to the C-subgenome of the hexaploid oat. The "malt" and "green" alpha-amylases in hexaploid and tetraploid oats have been identified. Isozymes of "green" alpha-amylase were lower in electrophoretic mobility than other isozymes and were governed by loci assigned to the A- and D-subgenomes. PMID:9775349

  4. Domain B protruding at the third beta strand of the alpha/beta barrel in barley alpha-amylase confers distinct isozyme-specific properties.

    PubMed

    Rodenburg, K W; Juge, N; Guo, X J; Søgaard, M; Chaix, J C; Svensson, B

    1994-04-01

    alpha-Amylases belong to the alpha/beta-barrel protein family in which the active site is created by residues located at the C-terminus of the beta strands and in the helix-connecting loops extending from these ends. In the alpha-amylase family, a small separate domain B protrudes at the C-terminus of the third beta strand of the (beta/alpha)8-barrel framework. The 80% identical barley alpha-amylase isozymes 1 and 2 (AMY1 and AMY2, respectively) differ in substrate affinity and turnover rate, CaCl2 stimulation of activity, sensitivity to the endogenous 21-kDa alpha-amylase/subtilisin inhibitor, and stability at low pH. To identify regions that confer these isozyme-specific variations, AMY1-AMY2 hybrid cDNAs were generated by in vivo homologous recombination in yeast. The hybrids AMY1-(1-90)-AMY2-(90-403) and AMY1-(1-161)-AMY2-(161-403) characterized in this study contain the 90-residue and 161-residue N-terminal sequences, respectively, of AMY1 and complementary C-terminal regions of AMY2. AMY1-(1-90)-AMY2-(90-403) comprises the 60-amino-acid domain B of AMY2 and resembles this isozyme in sensitivity to alpha-amylase/subtilisin inhibitor and its low affinity for the substrates p-nitrophenyl alpha-D-maltoheptaoside, amylose and the inhibitor acarbose. Only AMY1-(1-161)-AMY2-(161-403) and AMY1, which both share domain B, are stable at low pH. However, AMY2 and both hybrid AMY species, but not AMY1, show maximum enzyme activity on insoluble blue starch at approximately 10 mM CaCl2. Domain B thus determines several functional and stability properties that distinguish the barley alpha-amylase isozymes. PMID:8168517

  5. Clinical and immunological responses to occupational exposure to alpha-amylase in the baking industry.

    PubMed Central

    Brisman, J; Belin, L

    1991-01-01

    alpha-Amylase is a starch cleaving enzyme often used in the baking industry as a flour additive. It is usually of fungal origin, produced by Aspergillus oryzae. One previous report has shown IgE antibodies and positive skin prick test against alpha-amylase in asthmatic bakers. This paper describes four alpha-amylase sensitised index cases with occupational asthma or rhinitis and the results of a cross sectional study of 20 workers from the same factory who were also exposed to alpha-amylase powder. Air sampling detected airborne alpha-amylase at a concentration of 0.03 mg/m3. Significantly more work related symptoms such as rhinitis and dermatitis were found among the alpha-amylase exposed workers compared with referents. A skin prick test to alpha-amylase was positive in 30% (6/20) of the exposed workers. Most of the persons showing a positive skin prick test had work related symptoms and were also skin prick test positive to common allergens. Nasal challenge tests with amylase were performed in selected cases and validated three cases of alpha-amylase induced rhinitis. Two non-symptomatic workers had precipitins to alpha-amylase. Specific IgG antibodies were shown by two further serological techniques. The nature and relevance of these antibodies are currently being studied. It is concluded that alpha-amylase powder is a potent occupational sensitiser. Precautions should be taken when handling this allergenic enzyme. PMID:1832939

  6. Clinical and immunological responses to occupational exposure to alpha-amylase in the baking industry.

    PubMed

    Brisman, J; Belin, L

    1991-09-01

    alpha-Amylase is a starch cleaving enzyme often used in the baking industry as a flour additive. It is usually of fungal origin, produced by Aspergillus oryzae. One previous report has shown IgE antibodies and positive skin prick test against alpha-amylase in asthmatic bakers. This paper describes four alpha-amylase sensitised index cases with occupational asthma or rhinitis and the results of a cross sectional study of 20 workers from the same factory who were also exposed to alpha-amylase powder. Air sampling detected airborne alpha-amylase at a concentration of 0.03 mg/m3. Significantly more work related symptoms such as rhinitis and dermatitis were found among the alpha-amylase exposed workers compared with referents. A skin prick test to alpha-amylase was positive in 30% (6/20) of the exposed workers. Most of the persons showing a positive skin prick test had work related symptoms and were also skin prick test positive to common allergens. Nasal challenge tests with amylase were performed in selected cases and validated three cases of alpha-amylase induced rhinitis. Two non-symptomatic workers had precipitins to alpha-amylase. Specific IgG antibodies were shown by two further serological techniques. The nature and relevance of these antibodies are currently being studied. It is concluded that alpha-amylase powder is a potent occupational sensitiser. Precautions should be taken when handling this allergenic enzyme. PMID:1832939

  7. Alpha-amylase from the Hyperthermophilic Archaeon Thermococcus thioreducens

    NASA Technical Reports Server (NTRS)

    Bernhardsdotter, E. C. M. J.; Pusey, M. L.; Ng, M. L.; Garriott, O. K.

    2003-01-01

    Extremophiles are microorganisms that thrive in, from an anthropocentric view, extreme environments such as hot springs. The ability of survival at extreme conditions has rendered enzymes from extremophiles to be of interest in industrial applications. One approach to producing these extremozymes entails the expression of the enzyme-encoding gene in a mesophilic host such as E.coli. This method has been employed in the effort to produce an alpha-amylase from a hyperthermophile (an organism that displays optimal growth above 80 C) isolated from a hydrothermal vent at the Rainbow vent site in the Atlantic Ocean. alpha-amylases catalyze the hydrolysis of starch to produce smaller sugars and constitute a class of industrial enzymes having approximately 25% of the enzyme market. One application for thermostable alpha-amylases is the starch liquefaction process in which starch is converted into fructose and glucose syrups. The a-amylase encoding gene from the hyperthermophile Thermococcus thioreducens was cloned and sequenced, revealing high similarity with other archaeal hyperthermophilic a-amylases. The gene encoding the mature protein was expressed in E.coli. Initial characterization of this enzyme has revealed an optimal amylolytic activity between 85-90 C and around pH 5.3-6.0.

  8. Characterization of the L. manihotivorans alpha-amylase gene.

    PubMed

    Morlon-Guyot, J; Mucciolo-Roux, F; Rodriguez Sanoja, R; Guyot, J P

    2001-07-01

    Primers and probes were established from the sequences of the alpha-amylase genes (amyA) of L. amylovorus CIP 102989 and of L. plantarum A6 (Giraud and Cuny 1997). They were successfully used for the detection of the amyA gene in L. manihotivorans strain LMG 18010T and a 2842 bp region, containing the entire gene (2706 bp) with its putative promoter has been sequenced. More than 98% nucleotide sequence identities was found with L. amylovorus and L. plantarum amyA genes. The deduced amino acid sequence shares more than 96% amino acid sequence identities with L. amylovorus and L. plantarum alpha-amylases, and also 65% and 59% identities with the alpha-amylases of B. subtilis and S. bovis, respectively. The 3' terminal part of L. manihotivorans LMG 18010T amyA gene contained four repeated sequences (SRU). The amyA genes of the three lactobacilli species differed mainly in the number of SRU and in the size of the flanking regions of the SRU. PMID:11697143

  9. Thermal stability of alpha-amylase in aqueous cosolvent systems.

    PubMed

    Yadav, Jay Kant; Prakash, V

    2009-09-01

    The activity and thermal stability of alpha-amylase were studied in the presence of different concentrations of trehalose, sorbitol, sucrose and glycerol. The optimum temperature of the enzyme was found to be 50 +/- 2 degrees C. Further increase in temperature resulted in irreversible thermal inactivation of the enzyme. In the presence of cosolvents, the rate of thermal inactivation was found to be significantly reduced. The apparent thermal denaturation temperature (Tm) app and activation energy (Ea) of alpha-amylase were found to be significantly increased in the presence of cosolvents in a concentration-dependent manner. In the presence of 40% trehalose, sorbitol, sucrose and glycerol, increments in the (Tm)app were 20 degrees C, 14 degrees C, 13 degrees C and 9 degrees C, respectively. The Ea of thermal denaturation of alpha-amylase in the presence of 20% (w/v) trehalose, sorbitol, sucrose and glycerol was found to be 126, 95, 90 and 43 kcal/mol compared with a control value of 40 kcal/mol. Intrinsic and 8-anilinonaphathalene-1-sulphonic acid (ANS) fluorescence studies indicated that thermal denaturation of the enzyme was accompanied by exposure of the hydrophobic cluster on the protein surface. Preferential interaction parameters indicated extensive hydration of the enzyme in the presence of cosolvents. PMID:19805899

  10. THE CELL-BOUND ALPHA-AMYLASES OF STREPTOCOCCUS BOVIS.

    PubMed

    WALKER, G J

    1965-02-01

    1. The cell-bound alpha-amylase of Streptococcus bovis has been isolated from other carbohydrases in the cell extract by chromatography on DEAE-cellulose. The enzyme has been compared with the extracellular alpha-amylase produced by this organism. 2. The two amylases had similar action patterns on amylose, the main product being maltotriose with smaller amounts of maltose and a little glucose. 3. The cell-bound amylase hydrolysed maltopentaose and maltohexaose at a similar rate to the hydrolysis of amylose. Maltotetraose was hydrolysed six times more slowly, and maltotriose 280 times more slowly, than amylose. 4. Studies with end-labelled maltodextrins revealed that the cell-bound alpha-amylase preferentially hydrolysed the third linkage from the non-reducing end, liberating maltotriose. The linkage at the reducing end of maltotriose was more easily hydrolysed than the other. 5. Egg-white lysozyme and the extracellular enzymes of Streptomyces albus lysed the cell walls of Streptococcus bovis, releasing amylase into the medium. In the presence of 0.6 m-sucrose 10% of the maximal amylase activity was released by lysozyme. Suspension of the spheroplasts in dilute buffer caused the rupture of the cytoplasmic membrane and the liberation of amylase. 6. A sensitive method for determining the ability of amylases to degrade starch granules is described. PMID:14346085

  11. Action of human pancreatic and salivary alpha-amylases on maltooligosaccharides: evaluation of kinetic parameters.

    PubMed

    Saito, N; Horiuchi, T; Yoshida, M; Imai, T

    1979-10-01

    The kinetic studies on the reactions of human pancreatic and salivary alpha-amylases with several maltooligosaccharides (maltotetraose, maltopentaose, maltohexaose, and maltoheptaose) were carried out. The susceptibility to hydrolysis with human pancreatic alpha-amylase decreased in the order of maltopentaose, maltohexaose, maltotetraose, and maltoheptaose, while with human salivary alpha-amylase maltopentaose was hydrolysed slightly slower than maltohexaose but fairly faster than maltotetraose or maltoheptaose from a viewpoint of the rates of reactions based on the amount of substrate changed. The relative rates of production of substrates, utilized in the coupled yeast alpha-glucosidase reaction, increased in the order of maltoheptaose, maltohexaose, maltotetraose, and maltopentaose with human pancreatic alpha-amylase, while with human salivary alpha-amylase in the order of maltoheptaose, maltotetraose, maltohexaose, and maltopentaose. Thus, maltopentaose was considered to be the best substrate over maltotetraose, maltohexaose or maltoheptaose for the alpha-glucosidase coupled method of alpha-amylase determination. PMID:385176

  12. A comparison of ghrelin, glucose, alpha-amylase and protein levels in saliva from diabetics.

    PubMed

    Aydin, Suleyman

    2007-01-31

    During the past decade, many salivary parameters have been used to characterize disease states. Ghrelin (GAH) is recently-discovered peptide hormone secreted mainly from the stomach but also produced in a number of other tissues including salivary glands. The aim of this work was to examine the relationship between active (aGAH) and inactive (dGAH) ghrelin in the saliva and other salivary parameters in type II diabetic patients and healthy controls. Salivary parameters were assessed in a single measurement of unstimulated whole saliva from 20 obese and 20 non-obese type II diabetes patients, and in 22 healthy controls. Total protein and alpha-amylase were determined by colorimetric methods, and glucose by the glucose-oxidase method. Saliva aGAH and dGAH levels were measured using a commercial radioimmunoassay (RIA) kit. Salivary concentrations of aGAH and dGAH ghrelin were more markedly decreased in obese diabetic subjects than in the two other groups. Glucose and alpha-amylase levels were higher in diabetic subjects than in controls. Furthermore, there were correlations between GAH levels and BMI, and between GAH and blood pressure. However, there was no marked variability in saliva flow rates among the groups. These results indicate that measurement of salivary GAH and its relationship to other salivary parameters might help to provide insight into the role of ghrelin in diabetes. PMID:17244479

  13. Alpha amylase enzyme inhibitory and anti-inflammatory effect of Lawsonia inermis.

    PubMed

    Imam, Hasan; Mahbub, Nasir Uddin; Khan, Md Forhad; Hana, Humayera Kabir; Sarker, Md Moklesur Rahman

    2013-12-01

    Previously it was reported elsewhere that Lawsonia inermis have anti-inflammatory and analgesic effect in experimental animals. The in vitro porcine alpha amylase inhibitory effect was investigated of this plant methanolic extracts and consequently hypoglycemic effect by quantitatively determining the maltose from the maltose standard curve while the anti-inflammatory effect by acetic acid induced writhing test in mice. Acarbose (10 microg mL(-1)) and Diclofenac sodium (20 mg kg(-1)) were used as reference hypoglycemic and anti-inflammatory drugs, respectively, for this study. The methanolic leaves extract of the plant significantly inhibited (60.97% compared to untreated) enzymatic activity of the amylase at 10 microg mL(-1) dose (p < 0.05) also reduced the chemically induced nociceptive pain stimuli significantly at all doses (p < 0.01). Carbohydrates, glycosides, flavonoids, saponins and tannins were found to have in phytochemical screening of the extract which are thought to bring these effects. For the conclusive purpose, it is suggesting from the result that the pharmacological properties of this Lawsonia inermis can elicit hypoglycemic effect by inhibiting alpha-amylase enzyme and can reduce neurogenic pain stimulus. It gives the notion that how this group of patient would be therapeutically benefitted by decreasing both these effects by the same agent which is easy available. PMID:24506051

  14. Biochemical properties of alpha-amylase from peel of Citrus sinensis cv. Abosora.

    PubMed

    Mohamed, Saleh Ahmed; Drees, Ehab A; El-Badry, Mohamed O; Fahmy, Afaf S

    2010-04-01

    alpha-Amylase activity was screened in the peel, as waste fruit, of 13 species and cultivars of Egyptian citrus. The species Citrus sinensis cv. Abosora had the highest activity. alpha-Amylase AI from Abosora peel was purified to homogeneity using anion and cation-exchange, and gel filtration chromatographies. Molecular weight of alpha-amylase AI was found to be 42 kDa. The hydrolysis properties of alpha-amylase AI toward different substrates indicated that corn starch is the best substrate. The alpha-amylase had the highest activity toward glycogen compared with amylopectin and dextrin. Potato starch had low affinity toward alpha-amylase AI but it did not hydrolyze beta-cyclodextrin and dextran. Apparent Km for alpha-amylase AI was 5 mg (0.5%) starch/ml. alpha-Amylase AI showed optimum activity at pH 5.6 and 40 degrees C. The enzyme was thermally stable up to 40 degrees C and inactivated at 70 degrees C. The effect of mono and divalent metal ions were tested for the alpha-amylase AI. Ba2+ was found to have activating effect, where as Li+ had negligible effect on activity. The other metals caused inhibition effect. Activity of the alpha-amylase AI was increased one and half in the presence of 4 mM Ca2+ and was found to be partially inactivated at 10 mM Ca2+. The reduction of starch viscosity indicated that the enzyme is endoamylase. The results suggested that, in addition to citrus peel is a rich source of pectins and flavanoids, alpha-amylase AI from orange peel could be involved in the development and ripening of citrus fruit and may be used for juice processing. PMID:19941088

  15. Cloning of a yeast alpha-amylase promoter and its regulated heterologous expression

    DOEpatents

    Gao, Johnway [Richland, WA; Skeen, Rodney S [Pendleton, OR; Hooker, Brian S [Kennewick, WA; Anderson, Daniel B [Pasco, WA

    2003-04-01

    The present invention provides the promoter clone discovery of an alpha-amylase gene of a starch utilizing yeast strain Schwanniomyces castellii. The isolated alpha-amylase promoter is an inducible promoter, which can regulate strong gene expression in starch culture medium.

  16. Salivary Alpha-Amylase Reactivity in Breast Cancer Survivors

    PubMed Central

    Wan, Cynthia; Couture-Lalande, Marie-Ève; Narain, Tasha A.; Lebel, Sophie; Bielajew, Catherine

    2016-01-01

    The two main components of the stress system are the hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenal-medullary (SAM) axes. While cortisol has been commonly used as a biomarker of HPA functioning, much less attention has been paid to the role of the SAM in this context. Studies have shown that long-term breast cancer survivors display abnormal reactive cortisol patterns, suggesting a dysregulation of their HPA axis. To fully understand the integrity of the stress response in this population, this paper explored the diurnal and acute alpha-amylase profiles of 22 breast cancer survivors and 26 women with no history of cancer. Results revealed that breast cancer survivors displayed identical but elevated patterns of alpha-amylase concentrations in both diurnal and acute profiles relative to that of healthy women, F (1, 39) = 17.95, p < 0.001 and F (1, 37) = 7.29, p = 0.010, respectively. The average area under the curve for the diurnal and reactive profiles was 631.54 ± 66.94 SEM and 1238.78 ± 111.84 SEM, respectively. This is in sharp contrast to their cortisol results, which showed normal diurnal and blunted acute patterns. The complexity of the stress system necessitates further investigation to understand the synergistic relationship of the HPA and SAM axes. PMID:27023572

  17. Circadian rhythm of alpha-amylase in rat parotid gland.

    PubMed

    Bellavía, S L; Sanz, E G; Chiarenza, A P; Sereno, R; Vermouth, N T

    1990-01-01

    The circadian rhythm of alpha-amylase, E.C. 3.2.1.1. (alpha-1,4-glucan-4-glucanohydrolase) in parotid gland of 25 day old rats was studied under different experimental conditions (fast, reversed photoperiod, constant light or darkness and treatment with reserpine and alpha-methyl-p-tyrosine). The rhythm of rats fasted or exposed for 7 days to constant darkness did not change. There were modifications in the rhythm of rats submitted to a reversed photoperiod and it disappeared in animals submitted to constant light or darkness for 15 days or treated with reserpine or alpha-methyl-p-tyrosine. The rhythm persisted, with minor changes in the acrophase, in parotids of rats kept during their gestation and post-natal life in constant light or darkness. Results suggest that the circadian rhythm of alpha-amylase in parotid gland of young rats is endogenous, synchronized by the photoperiod, under autonomous nervous system control and maternal coordination. This model appears to be useful in the study of sympathetic nervous system control of target organs and circadian rhythms in general. PMID:2076161

  18. High-activity barley alpha-amylase by directed evolution.

    PubMed

    Wong, Dominic W S; Batt, Sarah B; Lee, Charles C; Robertson, George H

    2004-10-01

    Barley alpha-amylase isozyme 2 was cloned into and constitutively secreted by Saccharomyces cervisiae. The gene coding for the wild-type enzyme was subjected to directed evolution. Libraries of mutants were screened by halo formation on starch agar plates, followed by high-throughput liquid assay using dye-labeled starch as the substrate. The concentration of recombinant enzyme in the culture supernatant was determined by immunodetection, and used for the calculation of specific activity. After three rounds of directed evolution, one mutant (Mu322) showed 1000 times the total activity and 20 times the specific activity of the wild-type enzyme produced by the same yeast expression system. Comparison of the amino acid sequence of this mutant with the wild type revealed five substitutions: Q44H, R303K and F325Y in domain A, and T94A and R128Q in domain B. Two of these mutations. Q44H and R303K, result in amino acids highly conserved in cereal alpha-amylases. R303K and F325Y are located in the raw starch-binding fragment of the enzyme molecule. PMID:15635937

  19. Comparison of alpha-amylase activity in larval stages of flour beetles, Tribolium confusum (Coleoptera: Tenebionidae).

    PubMed

    Bandani, A R; Balvasi, A

    2006-01-01

    Flour beetles attack stored grain products such as flour, cereals, meal, dried pet food, dried flowers and even dried museum specimens and other foods in the house. Stored-product insects cause tremendous losses by lowering weight, germination rate, nutritional value and grain grade. These beetles are of the most important pests of stored products in the home and grocery stores. The adult female may live for as long as two years, depositing 300 to 400 eggs. The life cycle requires one to four months when temperatures are favorable. Several methods could be used to control this insect including synthetic insecticides, biological control, physical control and transgenic plant carrying gene of interest. Chemical controls are discouraged due to pesticide residue in the commodities and resistance in insects. The study of insect digestive enzymes seems to make sense in the realization that the gut is the major interface between the insect and its environment. Hence, an understanding of digestive enzyme function is essential when developing methods of insect control such as the use of enzyme inhibitors and transgenic plants to control insect pests. Therefore, the aim of the current study was to get a good understanding from enzyme composition of different larval stages of the insect and finally characterize amylase which is the key enzyme in digestive system of this insect. For alpha-amylase study whole larvae were homogenized in 0.02 M phosphate buffer at pH 7.2. The homogenates were separately transferred to a 1.5 ml of centrifuge tubes and centrifuged at 15000xg for 20 min at 4degrees C. The supernatants were used as enzyme source in assays. alpha-Amylase activity was assayed by the dinitrosalicylic acid (DNS) procedure using 1% soluble starch (Merck) as substrate. The results show that enzyme activity (OD) in the first, second, third and fourth larval stages were 0.5, 1.15, 1.35 and 1.362, respectively. There are significant differences in amylase activity in

  20. alpha-Amylase production in high cell density submerged cultivation of Aspergillus oryzae and A. nidulans.

    PubMed

    Agger, T; Spohr, A B; Nielsen, J

    2001-01-01

    The effect of biomass concentration on the formation of Aspergillus oryzae alpha-amylase during submerged cultivation with A. oryzae and recombinant A. nidulans strains has been investigated. It was found that the specific rate of alpha-amylase formation in chemostats decreased significantly with increasing biomass concentration in the range of approx. 2-12 g dry weight kg(-1). When using a recombinant A. nidulans strain in which the gene responsible for carbon catabolite repression of the A. oryzae alpha-amylase gene (creA) was deleted, no significant decrease in the specific rate of alpha-amylase formation was observed. On the basis of the experimental results, it is suggested that the low value of the specific alpha-amylase productivity observed at high biomass concentration is caused by slow mixing of the concentrated feed solution in the viscous fermentation medium. PMID:11234963

  1. Crystal and molecular structure of barley alpha-amylase.

    PubMed

    Kadziola, A; Abe, J; Svensson, B; Haser, R

    1994-05-27

    The three-dimensional structure of barley malt alpha-amylase (isoform AMY2-2) was determined by multiple isomorphous replacement using three heavy-atom derivatives and solvent flattening. The model was refined using a combination of simulated annealing and conventional restrained least-squares crystallographic refinement to an R-factor of 0.153 based on 18,303 independent reflections with F(o) > sigma(F(o)) between 10 and 2.8 A resolution, with root-mean-square deviations of 0.016 A and 3.3 degrees from ideal bond lengths and bond angles, respectively. The final model consists of 403 amino acid residues, three calcium ions and 153 water molecules. The polypeptide chain folds into three domains: a central domain forming a (beta alpha)8-barrel of 286 residues, with a protruding irregular structured loop domain of 64 residues (domain B) connecting strand beta 3 and helix alpha 3 of the barrel, and a C-terminal domain of 53 residues forming a five stranded anti-parallel beta-sheet. Unlike the previously known alpha-amylase structures, AMY2-2 contains three Ca2+ binding sites co-ordinated by seven or eight oxygen atoms from carboxylate groups, main-chain carbonyl atoms and water molecules, all calcium ions being bound to domain B and therefore essential for the structural integrity of that domain. Two of the Ca2+ sites are located only 7.0 A apart with one Asp residue serving as ligand for both. One Ca2+ site located at about 20 A from the other two was found to be exchangeable with Eu3+. By homology with other alpha-amylases, some important active site residues are identified as Asp179, Glu204 and Asp289, and are situated at the C-terminal end of the central beta-barrel. A starch granule binding site, previously identified as Trp276 and Trp277, is situated on alpha-helix 6 in the central (beta alpha)8-barrel, at the surface of the enzyme. This binding site region is associated with a considerable disruption of the (beta alpha)8-barrel 8-fold symmetry. PMID:8196040

  2. Optimization of alpha-amylase immobilization in calcium alginate beads.

    PubMed

    Ertan, Figen; Yagar, Hulya; Balkan, Bilal

    2007-01-01

    alpha-Amylase enzyme was produced by Aspergillus sclerotiorum under SSF conditions, and immobilized in calcium alginate beads. Effects of immobilization conditions, such as alginate concentration, CaCl(2) concentration, amount of loading enzyme, bead size, and amount of beads, on enzymatic activity were investigated. Optimum alginate and CaCl(2) concentration were found to be 3% (w/v). Using a loading enzyme concentration of 140 U mL(-1), and bead (diameter 3 mm) amount of 0.5 g, maximum enzyme activity was observed. Beads prepared at optimum immobilization conditions were suitable for up to 7 repeated uses, losing only 35% of their initial activity. Among the various starches tested, the highest enzyme activity (96.2%) was determined in soluble potato starch hydrolysis for 120 min at 40 degrees C. PMID:17516249

  3. Protein engineering in the alpha-amylase family: catalytic mechanism, substrate specificity, and stability.

    PubMed

    Svensson, B

    1994-05-01

    Most starch hydrolases and related enzymes belong to the alpha-amylase family which contains a characteristic catalytic (beta/alpha)8-barrel domain. Currently known primary structures that have sequence similarities represent 18 different specificities, including starch branching enzyme. Crystal structures have been reported in three of these enzyme classes: the alpha-amylases, the cyclodextrin glucanotransferases, and the oligo-1,6-glucosidases. Throughout the alpha-amylase family, only eight amino acid residues are invariant, seven at the active site and a glycine in a short turn. However, comparison of three-dimensional models with a multiple sequence alignment suggests that the diversity in specificity arises by variation in substrate binding at the beta-->alpha loops. Designed mutations thus have enhanced transferase activity and altered the oligosaccharide product patterns of alpha-amylases, changed the distribution of alpha-, beta- and gamma-cyclodextrin production by cyclodextrin glucanotransferases, and shifted the relative alpha-1,4:alpha-1,6 dual-bond specificity of neopullulanase. Barley alpha-amylase isozyme hybrids and Bacillus alpha-amylases demonstrate the impact of a small domain B protruding from the (beta/alpha)8-scaffold on the function and stability. Prospects for rational engineering in this family include important members of plant origin, such as alpha-amylase, starch branching and debranching enzymes, and amylomaltase. PMID:8018865

  4. Synergistic action of. alpha. -amylase and glucoamylase on hydrolysis of starch

    SciTech Connect

    Fujii, M.; Kawamura, Y.

    1985-03-01

    Synergistic action of ..alpha..-amylase and glucoamylase on hydrolysis of starch is modeled by the kinetic equations presented in this paper. At the early stage of the reaction ..alpha..-amylase acts as a contributor of newly formed non-reducing ends of starch molecules to glucoamylase by splitting the original starch molecules. This is expressed by the simultaneous differential equations which consist of each rate equation for ..alpha.. amylase and glucoamylase. After the molecular weight of the substrate decreases to the value of about 5000, which is obtained experimentally in this work, the action of ..alpha.. amylase can be neglected and the rate of formation of glucose obeys only the rate equation for glucoamylase. 5 references.

  5. Effect of oilseed cakes on alpha-amylase production by Bacillus licheniformis CUMC305.

    PubMed Central

    Krishnan, T; Chandra, A K

    1982-01-01

    The effects of oilseed cakes on extracellular thermostable alpha-amylase production by Bacillus licheniformis CUMC305 was investigated. Each oilseed cake was made of groundnut, mustard, sesame, linseed, coconut copra, madhuca, or cotton. alpha-Amylase production was considerably improved in all instances and varied with the oilseed cake concentration in basal medium containing peptone and beef extract. Maximum increases were effected by a low concentration (0.5 to 1.0%) of groundnut or coconut, a high concentration (3%) of linseed or mustard, and an Rintermediate concentration (2%) of cotton, madhuca, or sesame. The oilseed cakes made of groundnut or mustard could completely replace the conventional peptone-beef extract medium as the fermentation base for the production of alpha-amylase by B. licheniformis. The addition of corn steep liquor to cotton, linseed, sesame, or madhuca cake in the medium improved alpha-amylase production. PMID:6181738

  6. Effect of oilseed cakes on alpha-amylase production by Bacillus licheniformis CUMC305.

    PubMed

    Krishnan, T; Chandra, A K

    1982-08-01

    The effects of oilseed cakes on extracellular thermostable alpha-amylase production by Bacillus licheniformis CUMC305 was investigated. Each oilseed cake was made of groundnut, mustard, sesame, linseed, coconut copra, madhuca, or cotton. alpha-Amylase production was considerably improved in all instances and varied with the oilseed cake concentration in basal medium containing peptone and beef extract. Maximum increases were effected by a low concentration (0.5 to 1.0%) of groundnut or coconut, a high concentration (3%) of linseed or mustard, and an Rintermediate concentration (2%) of cotton, madhuca, or sesame. The oilseed cakes made of groundnut or mustard could completely replace the conventional peptone-beef extract medium as the fermentation base for the production of alpha-amylase by B. licheniformis. The addition of corn steep liquor to cotton, linseed, sesame, or madhuca cake in the medium improved alpha-amylase production. PMID:6181738

  7. Isozyme hybrids within the protruding third loop domain of the barley alpha-amylase (beta/alpha)8-barrel. Implication for BASI sensitivity and substrate affinity.

    PubMed

    Juge, N; Rodenburg, K W; Guo, X J; Chaix, J C; Svensson, B

    1995-04-24

    Barley alpha-amylase isozymes AMY1 and AMY2 contain three structural domains: a catalytic (beta/alpha)8-barrel (domain A) with a protruding loop (domain B; residues 89-152) that binds Ca2+, and a small C-terminal domain. Different parts of domain B secure isozyme specific properties as identified for three AMY1-AMY2 hybrids, obtained by homeologous recombination in yeast, with crossing-over at residues 112, 116, and 144. The AMY1 regions Val90-Thr112 and Ala145-Leu161 thus confer high affinities for the substrates alpha-D-maltoheptaoside and amylose, respectively. Leu117-Phe144, and to a lesser degree Ala145-Leu161, are critical for the stability at low pH characteristic of AMY1 and for the sensitivity to barley alpha-amylase/subtilisin inhibitor specific to AMY2. PMID:7737421

  8. alpha. -Amylase of Clostridium thermosulfurogenes EM1: Nucleotide sequence of the gene, processing of the enzyme, and comparison to other. alpha. -amylases

    SciTech Connect

    Bahl, H.; Burchhardt, G.; Spreinat, A.; Haeckel, K.; Wienecke, A.; Antranikian, G.; Schmidt, B. )

    1991-05-01

    The nucleotide sequence of the {alpha}-amylase gene (amyA) from Clostridium thermosulfurogenes EM1 cloned in Escherichia coli was determined. The reading frame of the gene consisted of 2,121 bp. Comparison of the DNA sequence data with the amino acid sequence of the N terminus of the purified secreted protein of C. thermosulfurogenes Em1 suggested that the {alpha}-amylase is translated form mRNA as a secretory precursor with a signal peptide of 27 amino acid residues. The deduced amino acid sequence of the mature {alpha}-amylase contained 679 residues, resulting in a protein with a molecular mass of 75,112 Da. In E. coli the enzyme was transported to the periplasmic space and the signal peptide was cleaved at exactly the same site between two alanine residues. Comparison of the amino acid sequence of the C. thermosulfurogenes EM1 {alpha}-amylase with those from other bacterial and eukaryotic {alpha}-amylases showed several homologous regions, probably in the enzymatically functioning regions. The tentative Ca{sup 2+}-binding site (consensus region I) of this Ca{sub 2+}-independent enzyme showed only limited homology. The deduced amino acid sequence of a second obviously truncated open reading frame showed significant homology to the malG gene product of E. coli. Comparison of the {alpha}-amylase gene region of C. thermosulfurogenes EM1 (DSM3896) with the {beta}-amylase gene region of C. thermosulfurogenes (ATCC 33743) indicated that both genes have been exchanged with each other at identical sites in the chromosomes of these strains.

  9. Exposure-sensitization relationship for alpha-amylase allergens in the baking industry.

    PubMed

    Houba, R; Heederik, D J; Doekes, G; van Run, P E

    1996-07-01

    Fungal alpha-amylase is an important occupational allergen in the bakery industry. Epidemiologic studies focusing on the relationship between alpha-amylase allergen exposure and work-related respiratory allergy, however, have not been reported yet. In this cross-sectional study, sensitization to occupational allergens and work-related symptoms were studied in 178 bakery workers and related to allergen exposure. Alpha-amylase allergen concentrations were measured in personal dust samples, using a sandwich enzyme immunoassay. All workers were categorized into groups on the basis of their job histories and the alpha-amylase exposure levels of their job titles. Of all workers 25% had one or more work-related symptoms. As much as 9% of the bakery workers showed a positive skin prick test reaction to fungal amylase, and in 8% amylase-specific IgE was demonstrated. Alpha-amylase exposure and atopy appeared to be the most important determinants of skin sensitization, with prevalence ratios for atopy of 20.8 (95% CI, 2.74 to 158) and for medium and high alpha-amylase exposure groups of 8.6 (95% CI, 1.01 to 74) and 15.9 (95% CI, 1.95 to 129), respectively. Furthermore, a positive association was found between positive skin prick tests to alpha-amylase and work-related respiratory symptoms. In conclusion, this study has shown that there is a strong and positive relationship between alpha-amylase allergen exposure levels in bakeries and specific sensitization in bakery workers. PMID:8680668

  10. [Cloning the alpha-amylase gene of Streptococcus bovis and its expression in Bacillus subtilis cells].

    PubMed

    Iakorski, P; Kuntsova, M M; Loseva, E F; Khasanov, F K

    1991-06-01

    The gene coding for alpha-amylase from the ruminant bacterium Streptococcus bovis was cloned on the plasmid pMX39 in Bacillus subtilis cells. An alpha-amylase positive colony was isolated in the initial screening of 3900 colonies on the medium containing insoluble starch. The size of the insert was approximately 2.8 kb. The recombinant plasmid was stably maintained in Bacillus subtilis cells under the nonselective conditions. PMID:1944323

  11. Psychological stress-induced changes in salivary alpha-amylase and adrenergic activity.

    PubMed

    Kang, Younhee

    2010-12-01

    The aim of the study was to examine the relationships among salivary alpha-amylase, plasma catecholamines, blood pressure, and heart rate during psychological stress. This study used a pretest-post-test experimental design with a control group, using repeated measures. A total of 33 participants was divided into the experimental group (n = 16) that underwent a college academic final test as the psychological stress and the control group (n = 17) that did not undergo the test. The levels of salivary alpha-amylase and plasma catecholamines, blood pressure, and heart rate were measured seven times and stress and anxiety were measured once and twice, respectively, as subjective stress markers. Significant changes in the level of salivary alpha-amylase were found in response to psychological stress. However, the correlations of salivary alpha-amylase with the plasma catecholamines, blood pressure, and heart rate were only partially found to be statistically significant. In conclusion, it was shown that salivary alpha-amylase was sensitive to stress throughout this study. Thus, salivary alpha-amylase may be used to measure stress uninvasively in both clinical settings and nursing research where the effects of stress might be scrutinized. Furthermore, the mechanisms of illnesses that are induced by stress could be explored. PMID:21210927

  12. Interparental Aggression and Parent-Adolescent Salivary Alpha Amylase Symmetry

    PubMed Central

    Gordis, Elana B.; Margolin, Gayla; Spies, Lauren; Susman, Elizabeth J.; Granger, Douglas A.

    2010-01-01

    The present study examined salivary alpha-amylase (sAA), a putative marker of adrenergic activity, in family members engaging in family conflict discussions. We examined symmetry among family members' sAA levels at baseline and in response to a conflict discussion. The relation between a history of interparental aggression on parent-adolescent sAA symmetry also was examined. Participants were 62 families with a mother, father, and biological child age 13-18 (n = 29 girls). After engaging in a relaxation procedure, families participated in a 15-minute triadic family conflict discussion. Participants provided saliva samples at post-relaxation/pre-discussion, immediately post-discussion, and at 10 and 20 min post-discussion. Participants also reported on interparental physical aggression during the previous year. Across the sample we found evidence of symmetry between mothers' and adolescents' sAA levels at baseline and around the discussion. Interparental aggression was associated with lower sAA levels among fathers. Interparental aggression also affected patterns of parent-child sAA response symmetry such that families reporting interparental aggression exhibited greater father-adolescent sAA symmetry than did those with no reports of interparental aggression. Among families with no interparental aggression history, we found consistent mother-adolescent symmetry. These differences suggest different patterns of parent-adolescent physiological attunement among families with interparental aggression. PMID:20096715

  13. Regulation of the synthesis of barley aleurone. cap alpha. -amylase by gibberellic acid and calcium ions

    SciTech Connect

    Jones, R.L.; Carbonell, J.

    1984-09-01

    The effects of gibberellic acid (GA/sub 3/) and calcium ions on the production of ..cap alpha..-amylase and acid phosphatase by isolated aleurone layers of barley (Hordeum vulgare L. cv Himalaya) were studied. Aleurone layers not previously exposed to GA/sub 3/ or CA/sup 2 +/ show qualitative and quantitative changes in hydrolase production following incubation in either GA/sub 3/ or CA/sup 2 +/ or both. In cubation in H/sub 2/O or CA/sup 2 +/ results in the production of low levels of ..cap alpha..-amylase or acid phosphatase. The addition of GA/sub 3/ to the incubation medium causes 10- to 20-fold increase in the amounts of these enzymes released from the tissue, and addition of CA/sup 2 +/ at 10 millimolar causes a further 8- to 9-fold increase in ..cap alpha..-amylase release and a 75% increase in phosphatase release. Production of ..cap alpha..-amylase isoenzymes is also modified by the levels of GA/sub 3/ and CA/sup 2 +/ in the incubation medium. ..cap alpha..-amylase 2 is produced under all conditions of incubation, while ..cap alpha..-amylase 1 appears only when layers are incubated in GA/sub 3/ or GA/sub 3/ plus CA/sup 2 +/. The synthesis of ..cap alpha..-amylases 3 and 4 requires the presence of both GA/sub 3/ and CA/sup 2 +/ in the incubation medium. Laurell rocket immunoelectrophoresis shows that two distinct groups of ..cap alpha..-amylase antigens are present in incubation media of aleurone layers incubated with both GA/sub 3/ and CA/sup 2 +/, while only one group of antigens is found in media of layers incubated in GA/sub 3/ alone. Strontium ions can be substituted for CA/sup 2 +/ in increasing hydrolase production, although higher concentrations of Sr/sup 2 +/ are requried for maximal response. We conclude that GA/sub 3/ is required for the production of ..cap alpha..-amylase 1 and that both GA/sub 3/ and either CA/sup 2 +/ or Sr/sup 2 +/ are required for the production of isoenzymes 3 and 4 of barley aleurone ..cap alpha..-amylase. 22 references, 8

  14. Purification, characterization, and nucleotide sequence of an intracellular maltotriose-producing alpha-amylase from Streptococcus bovis 148.

    PubMed

    Satoh, E; Uchimura, T; Kudo, T; Komagata, K

    1997-12-01

    An intracellular alpha-amylase from Streptococcus bovis 148 was purified and characterized. The enzyme was induced by maltose and soluble starch and produced about 80% maltotriose from soluble starch. Maltopentaose was hydrolyzed to maltotriose and maltose and maltohexaose was hydrolyzed mainly to maltotriose by the enzyme. Maltotetraose, maltotriose, and maltose were not hydrolyzed. This intracellular enzyme was considered to be a maltotriose-producing enzyme. The enzymatic characteristics and hydrolysis product from soluble starch were different from those of the extracellular raw-starch-hydrolyzing alpha-amylase of strain 148. The deduced amino acid sequence of the intracellular alpha-amylase was similar to the sequences of the mature forms of extracellular liquefying alpha-amylases from Bacillus strains, although the intracellular alpha-amylase did not contain a signal peptide. No homology between the intracellular and extracellular alpha-amylases of S. bovis 148 was observed. PMID:9406414

  15. Purification, characterization, and nucleotide sequence of an intracellular maltotriose-producing alpha-amylase from Streptococcus bovis 148.

    PubMed Central

    Satoh, E; Uchimura, T; Kudo, T; Komagata, K

    1997-01-01

    An intracellular alpha-amylase from Streptococcus bovis 148 was purified and characterized. The enzyme was induced by maltose and soluble starch and produced about 80% maltotriose from soluble starch. Maltopentaose was hydrolyzed to maltotriose and maltose and maltohexaose was hydrolyzed mainly to maltotriose by the enzyme. Maltotetraose, maltotriose, and maltose were not hydrolyzed. This intracellular enzyme was considered to be a maltotriose-producing enzyme. The enzymatic characteristics and hydrolysis product from soluble starch were different from those of the extracellular raw-starch-hydrolyzing alpha-amylase of strain 148. The deduced amino acid sequence of the intracellular alpha-amylase was similar to the sequences of the mature forms of extracellular liquefying alpha-amylases from Bacillus strains, although the intracellular alpha-amylase did not contain a signal peptide. No homology between the intracellular and extracellular alpha-amylases of S. bovis 148 was observed. PMID:9406414

  16. Decreased shoot stature and grain alpha-amylase activity following ectopic expression of a gibberellin 2-oxidase gene in transgenic wheat.

    PubMed

    Appleford, Nigel E J; Wilkinson, Mark D; Ma, Qian; Evans, Daniel J; Stone, Marlon C; Pearce, Stephen P; Powers, Stephen J; Thomas, Stephen G; Jones, Huw D; Phillips, Andrew L; Hedden, Peter; Lenton, John R

    2007-01-01

    Ectopic expression of a gibberellin 2-oxidase gene (PcGA2ox1) decreased the content of bioactive gibberellins (GAs) in transgenic wheat, producing a range of dwarf plants with different degrees of severity. In at least one case, a single transformation event gave rise to T(1) plants with different degrees of dwarfism, the phenotypes being stably inherited over at least four generations. The dwarf phenotype, which included dark-green leaves, increased tillering and, in severe cases, a prostrate growth habit, was replicated by the application of a GA biosynthesis inhibitor to the wild type. Ear rachis length, grain set, and grain size were also decreased in the wheat transformants, compared with an azygous (null) line. The extent of post-germination alpha-amylase production in grains reflected the severity of the shoot phenotype of the transformants and both developmental processes were restored to normal by the application of gibberellic acid (GA(3)). Expression of two GA biosynthesis genes (TaGA20ox1 and TaGA3ox2) was up-regulated, and that of two alpha-amylase gene families (alpha-Amy1 and alpha-Amy2) down regulated, in scutella of semi-dwarf lines, compared with controls. The marked decline in transcript abundance of both alpha-amylase gene families in aleurone was associated with a decreased content of bioactive GAs in grains of the semi-dwarf lines. PMID:17916639

  17. Purification and characterization of the extracellular alpha-amylase from Clostridium acetobutylicum ATCC 824.

    PubMed Central

    Paquet, V; Croux, C; Goma, G; Soucaille, P

    1991-01-01

    The extracellular alpha-amylase (1,4-alpha-D-glucanglucanohydrolase; EC 3.2.1.1) from Clostridium acetobutylicum ATCC 824 was purified to homogeneity by anion-exchange chromatography (mono Q) and gel filtration (Superose 12). The enzyme had an isoelectric point of 4.7 and a molecular weight of 84,000, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was a monomeric protein, the 19-amino-acid N terminus of which displayed 42% homology with the Bacillus subtilis saccharifying alpha-amylase. The amino acid composition of the enzyme showed a high number of acidic and hydrophobic residues and only one cysteine residue per mole. The activity of the alpha-amylase was not stimulated by calcium ions (or other metal ions) or inhibited by EDTA, although the enzyme contained seven calcium atoms per molecule. alpha-Amylase activity on soluble starch was optimal at pH 5.6 and 45 degrees C. The alpha-amylase was stable at an acidic pH but very sensitive to thermal inactivation. It hydrolyzed soluble starch, with a Km of 3.6 g . liter-1 and a Kcat of 122 mol of reducing sugars . s-1 . mol-1. The alpha-amylase showed greater activity with high-molecular-weight substrates than with low-molecular-weight maltooligosaccharides, hydrolyzed glycogen and pullulan slowly, but did not hydrolyze dextran or cyclodextrins. The major end products of maltohexaose degradation were glucose, maltose, and maltotriose; maltotetraose and maltopentaose were formed as intermediate products. Twenty seven percent of the glucoamylase activity generally detected in the culture supernatant of C. acetobutylicum can be attributed to the alpha-amylase. Images PMID:8967771

  18. Purification and characterization of the extracellular. alpha. -amylase from Clostridium acetobutylicum ATCC 824

    SciTech Connect

    Paquet, V.; Croux, C.; Goma, G.; Soucaille, P. )

    1991-01-01

    The extracellular {alpha}-amylase (1,4-{alpha}-D-glucanglucanohydrolase; EC 3.2.1.1) from Clostridium acetobutylicum ATCC 824 was purified to homogeneity by anion-exchange chromatography (Mono Q) and gel filtration (Superose 12). The enzyme had an isoelectric point of 4.7 and a molecular weight of 84,000, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was a monomeric protein, the 19-amino-acid N terminus of which displayed 42% homology with the Bacillus subtilis saccharifying {alpha}-amylase. The amino acid composition of the enzyme showed a high number of acidic and hydrophobic residues and only one cysteine residue per mole. The activity of the {alpha}-amylase was not stimulated by calcium ions (or other metal ions) or inhibited by EDTA, although the enzyme contained seven calcium atoms per molecule. {alpha}-Amylase activity on soluble starch was optimal at pH 5.6 and 45{degree}C. The {alpha}-amylase was stable at an acidic pH but very sensitive to thermal inactivation. It hydrolyzed soluble starch, with a K{sub m} of 3.6 g {center dot} liter{sup {minus}1} and a K{sub cat} of 122 mol of reducing sugars {center dot} s{sup {minus}1} {center dot} mol{sup {minus}1}. The {alpha}-amylase showed greater activity with high-molecular-weight substrates than with low-molecular-weight maltooligosaccharides, hydrolyzed glycogen and pullulan slowly, but did not hydrolyze dextran or cyclodextrins. The major end products of maltohexaose degradation were glucose, maltose, and maltotriose; maltotetraose and maltopentaose were formed as intermediate products. Twenty seven percent of the glucoamylase activity generally detected in the culture supernatant of C. acetobutylicum can be attributed to the {alpha}-amylase.

  19. Phylogenetic and Comparative Sequence Analysis of Thermostable Alpha Amylases of kingdom Archea, Prokaryotes and Eukaryotes.

    PubMed

    Huma, Tayyaba; Maryam, Arooma; Rehman, Shahid Ur; Qamar, Muhammad Tahir Ul; Shaheen, Tayyaba; Haque, Asma; Shaheen, Bushra

    2014-01-01

    Alpha amylase family is generally defined as a group of enzymes that can hydrolyse and transglycosylase α-(1, 4) or α-(1, 6) glycosidic bonds along with the preservation of anomeric configuration. For the comparative analysis of alpha amylase family, nucleotide sequences of seven thermo stable organisms of Kingdom Archea i.e. Pyrococcus furiosus (100-105°C), Kingdom Prokaryotes i.e. Bacillus licheniformis (90-95°C), Geobacillus stearothermophilus (75°C), Bacillus amyloliquefaciens (72°C), Bacillus subtilis (70°C) and Bacillus KSM K38 (55°C) and Eukaryotes i.e. Aspergillus oryzae (60°C) were selected from NCBI. Primary structure composition analysis and Conserved sequence analysis were conducted through Bio Edit tools. Results from BioEdit shown only three conserved regions of base pairs and least similarity in MSA of the above mentioned alpha amylases. In Mega 5.1 Phylogeny of thermo stable alpha amylases of Kingdom Archea, Prokaryotes and Eukaryote was handled by Neighbor-Joining (NJ) algorithm. Mega 5.1 phylogenetic results suggested that alpha amylases of thermo stable organisms i.e. Pyrococcus furiosus (100-105°C), Bacillus licheniformis (90-95°C), Geobacillus stearothermophilus (75°C) and Bacillus amyloliquefaciens (72°C) are more distantly related as compared to less thermo stable organisms. By keeping in mind the characteristics of most thermo stable alpha amylases novel and improved features can be introduced in less thermo stable alpha amylases so that they become more thermo tolerant and productive for industry. PMID:25187685

  20. Alpha-Amylase Activity in Blood Increases after Pharmacological, But Not Psychological, Activation of the Adrenergic System

    PubMed Central

    Nater, Urs M.; La Marca, Roberto; Erni, Katja; Ehlert, Ulrike

    2015-01-01

    Background & Aim Alpha-amylase in both blood and saliva has been used as a diagnostic parameter. While studies examining alpha-amylase activity in saliva have shown that it is sensitive to physiological and psychological challenge of the adrenergic system, no challenge studies have attempted to elucidate the role of the adrenergic system in alpha-amylase activity in blood. We set out to examine the impact of psychological and pharmacological challenge on alpha-amylase in blood in two separate studies. Methods In study 1, healthy subjects were examined in a placebo-controlled, double-blind paradigm using yohimbine, an alpha2-adrenergic antagonist. In study 2, subjects were examined in a standardized rest-controlled psychosocial stress protocol. Alpha-amylase activity in blood was repeatedly measured in both studies. Results Results of study 1 showed that alpha-amylase in blood is subject to stronger increases after injection of yohimbine compared to placebo. In study 2, results showed that there was no significant effect of psychological stress compared to rest. Conclusions Alpha-amylase in blood increases after pharmacological activation of the adrenergic pathways suggesting that sympathetic receptors are responsible for these changes. Psychological stress, however, does not seem to have an impact on alpha-amylase in blood. Our findings provide insight into the mechanisms underlying activity changes in alpha-amylase in blood in healthy individuals. PMID:26110636

  1. Stress affects salivary alpha-Amylase activity in bonobos.

    PubMed

    Behringer, Verena; Deschner, Tobias; Möstl, Erich; Selzer, Dieter; Hohmann, Gottfried

    2012-01-18

    Salivary alpha-Amylase (sAA) is a starch digesting enzyme. In addition to its function in the context of nutrition, sAA has also turned out to be useful for monitoring sympathetic nervous system activity. Recent studies on humans have found a relationship between intra-individual changes in sAA activity and physical and psychological stress. In studies on primates and other vertebrates, non-invasive monitoring of short-term stress responses is usually based on measurements of cortisol levels, which are indicative of hypothalamic-pituitary-adrenal activity. The few studies that have used both cortisol levels and sAA activity indicate that these two markers may respond differently and independently to different types of stress such that variation in the degree of the activation of different stress response systems might reflect alternative coping mechanisms or individual traits. Here, we present the first data on intra- and inter-individual variation of sAA activity in captive bonobos and compare the results with information from other ape species and humans. Our results indicate that sAA activity in the bonobo samples was significantly lower than in the human samples but within the range of other great ape species. In addition, sAA activity was significantly higher in samples collected at times when subjects had been exposed to stressors (judged by changes in behavioral patterns and cortisol levels) than in samples collected at other times. Our results indicate that bonobos possess functioning sAA and, as in other species, sAA activity is influenced by autonomic nervous system activity. Monitoring sAA activity could therefore be a useful tool for evaluating stress in bonobos. PMID:21945369

  2. The synergetic effect of starch and alpha amylase on the biodegradation of n-alkanes.

    PubMed

    Karimi, M; Biria, D

    2016-06-01

    The impact of adding soluble starch on biodegradation of n-alkanes (C10-C14) by Bacillus subtilis TB1 was investigated. Gas chromatography was employed to measure the residual hydrocarbons in the system. It was observed that the efficiency of biodegradation improved with the presence of starch and the obtained residual hydrocarbons in the system were 53% less than the samples without starch. The produced bacterial enzymes were studied through electrophoresis and reverse zymography for explaining the observations. The results indicated that the produced amylase by the bacteria can degrade hydrocarbons and the same was obtained by the application of a commercial alpha amylase sample. In addition, in silico docking of alpha-amylase with n-alkanes with different molecular weights was studied by Molegro virtual docker which showed high negative binding energies and further substantiated the experimental observations. Overall, the findings confirmed the catalytic effect of alpha amylase on n-alkanes degradation. PMID:26971168

  3. Study on alpha-amylase hydrolysis of potato amylopectin by a quartz crystal microbalance.

    PubMed

    Sasaki, Tomoko; Noel, Timothy R; Ring, Steve G

    2008-02-13

    Potato amylopectin with phosphate groups was immobilized on a quartz crystal microbalance with dissipation monitoring (QCMD) using the attractive interaction between opposite charges, and enzymatic starch hydrolysis was monitored directly. Poly( L-lysine) (PLL) proved to be an appropriate cationic linker between the QCMD silica sensor and potato amylopectin. Increased mass and dissipation were observed when amylopectin was adsorbed onto the PLL layer and reversed when alpha-amylase was added. The effect of chitosan with cationic property on the hydrolysis of amylopectin was studied. Chitosan was observed to be adsorbed onto the amylopectin surface and to suppress hydrolysis by alpha-amylase. The formation of alternating layers of amylopectin and chitosan was monitored by QCMD. Amylopectin-chitosan trilayers increased resistance to digestion by alpha-amylase compared to one layer and to control without chitosan. PMID:18181571

  4. RAmy2A; a novel alpha-amylase-encoding gene in rice.

    PubMed

    Huang, N; Reinl, S J; Rodriguez, R L

    1992-02-15

    The structure and expression of the alpha-amylase-encoding gene, RAmy2A, are described. This only representative of the Amy2 subfamily in rice differs from other cereal alpha-amylase-encoding genes in several respects. It contains the largest introns of all the cereal alpha-amylase-encoding genes examined to date. Moreover, the second of three introns in this gene contains a long inverted repeat sequence that can potentially form a large and stable stem-loop structure in the unspliced RNA transcript. Finally, RAmy2A is constitutively expressed at very low levels in germinated seeds, root, etiolated leaves, immature seeds and callus. This is in marked contrast to the Amy2 genes of wheat and barley which are highly expressed in the aleurone layer of the germinated seeds. PMID:1541400

  5. Differential expression of rice alpha-amylase genes during seedling development under anoxia.

    PubMed

    Hwang, Y S; Thomas, B R; Rodriguez, R L

    1999-08-01

    The unique capability of rice (Oryza sativa L.) seedlings to grow under anoxic conditions may result in part from their ability to express alpha-amylase and maintain the supply of sugar needed for energy metabolism. Previous studies have demonstrated that under aerobic conditions the Amy1 and Amy2 subfamily genes are regulated primarily by phytohormones while the Amy3 subfamily genes are induced during sugar starvation. The expression patterns for these alpha-amylase genes were considerably different in anoxic vs. aerobic rice seedlings. The level of total alpha-amylase mRNA under anoxic conditions was decreased in aleurone layers while it increased in the embryo. Anoxic conditions greatly diminished the expression of the Amy1A gene in aleurone. Conversely, expression of many Amy3 subfamily genes was up-regulated and prolonged in embryo tissues under anoxic conditions. PMID:10527416

  6. Thermal stability of alpha-amylase from Aspergillus oryzae entrapped in polyacrylamide gel.

    PubMed

    Raviyan, Patcharin; Tang, Juming; Rasco, Barbara A

    2003-08-27

    To determine the suitability as a time-temperature indicator for dielectric pasteurization processes, the thermal stability (50-75 degrees C) of Aspergillus oryzae alpha-amylase immobilized in polyacrylamide gel in phosphate buffer, mashed potatoes, and minced shrimp was examined. Changing the cross-linking agent concentration from 3.3 to 5.3% and adding 2% salt did not markedly affect the thermal stability of the immobilized alpha-amylase. Thermal inactivation was first order, and immobilization generally improved the thermal stability of alpha-amylase. z values of the immobilized system in test food systems were 10.2 degrees C (phosphate buffer), 8.45 degrees C (minced shrimp), and 7.78 degrees C (mashed potatoes). PMID:12926898

  7. Heterologous expression and secretion of Lactobacillus amylovorus alpha-amylase in Leuconostoc citreum.

    PubMed

    Eom, Hyun-Ju; Moon, Jin-Seok; Seo, Eun-Young; Han, Nam Soo

    2009-11-01

    To develop a gene expression system for Leuconostoc genus, construction of expression vector and expression of a heterologus protein in Leuconostoc was performed. Alpha-amylase gene from Lactobacillus amylovorus was cloned into a Leuconostoc cloning vector, pLeuCM, with its own signal peptide. pLeuCMamy was introduced into Leuconostoc citreum CB2567 and a successful expression of alpha-amy gene was confirmed by enzyme activity assays. About 90% of alpha-amylase activity was detected in the culture broth, revealing most of expressed alpha-amylase was secreted out cells. The signal sequence of alpha-amy gene is a good candidate for the secretion of heterologous protein by using Leuconostoc host-vector system. PMID:19618275

  8. Effect of sexual steroids upon ontogeny of alpha-amylase of rat parotid gland.

    PubMed

    Bellavia, S L; Sanz, E G; Vermouth, N T; Blanco, A

    1982-04-30

    The effect of gonadectomy (at the 10th day of life) and treatment with sexual steroids (during the first month) upon development of alpha-amylase activity in rat parotid gland has been studied. Alpha-amylase specific activity of parotid glands from 20-day-old orchidectomized rats and from 25-day-old ovariectomized animals was significantly higher than that of intact male and female rats of the same age respectively. Spayed males treated with testosterone (10 microgram/day on the 13th, 15th, and 17th day) and ovariectomized rats treated with oestradiol (2.5 microgram/day from the 16th to the 22nd day) showed values of enzymic activity similar to those of normal animals. Results indicate that oestradiol and testosterone have an inhibitory effect upon the increase of alpha-amylase activity in parotid gland during a very defined period of development. PMID:6178953

  9. General Subject 1. Report to ICUMSA on the determination of commercial alpha-amylase activity by a spectrophotometric method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A report is given on a new industrial method for the determination of the activity or strength of commercial alpha-amylase at a sugarcane factory or refinery, as well as a recommendation. At the present time, the activities or strengths of commercial alpha-amylases cannot be directly compared becau...

  10. Alternative catalytic anions differentially modulate human alpha-amylase activity and specificity.

    PubMed

    Maurus, Robert; Begum, Anjuman; Williams, Leslie K; Fredriksen, Jason R; Zhang, Ran; Withers, Stephen G; Brayer, Gary D

    2008-03-18

    A mechanistic study of the essential allosteric activation of human pancreatic alpha-amylase by chloride ion has been conducted by exploring a wide range of anion substitutions through kinetic and structural experiments. Surprisingly, kinetic studies indicate that the majority of these alternative anions can induce some level of enzymatic activity despite very different atomic geometries, sizes, and polyatomic natures. These data and subsequent structural studies attest to the remarkable plasticity of the chloride binding site, even though earlier structural studies of wild-type human pancreatic alpha-amylase suggested this site would likely be restricted to chloride binding. Notably, no apparent relationship is observed between anion binding affinity and relative activity, emphasizing the complexity of the relationship between chloride binding parameters and the activation mechanism that facilitates catalysis. Of the anions studied, particularly intriguing in terms of observed trends in substrate kinetics and their novel atomic compositions were the nitrite, nitrate, and azide anions, the latter of which was found to enhance the relative activity of human pancreatic alpha-amylase by nearly 5-fold. Structural studies have provided considerable insight into the nature of the interactions formed in the chloride binding site by the nitrite and nitrate anions. To probe the role such interactions play in allosteric activation, further structural analyses were conducted in the presence of acarbose, which served as a sensitive reporter molecule of the catalytic ability of these modified enzymes to carry out its expected rearrangement by human pancreatic alpha-amylase. These studies show that the largest anion of this group, nitrate, can comfortably fit in the chloride binding pocket, making all the necessary hydrogen bonds. Further, this anion has nearly the same ability to activate human pancreatic alpha-amylase and leads to the production of the same acarbose product

  11. Purification and characterization of periplasmic alpha-amylase from Xanthomonas campestris K-11151.

    PubMed Central

    Abe, J; Onitsuka, N; Nakano, T; Shibata, Y; Hizukuri, S; Entani, E

    1994-01-01

    Xanthomonas campestris K-11151, isolated from soil, produced a periplasmic alpha-amylase of a new type. The enzyme was purified to homogeneity, as shown by several criteria. The purified enzyme showed almost the same activities on alpha-, beta-, and gamma-cyclodextrins, soluble starch, and amylose. Moreover, it was active on branched cyclodextrins, pullulan, and maltose but not on glycogen. Kinetic analysis showed that alpha-cyclodextrin was the best substrate among the cyclodextrins. The substrate specificity suggested that this enzyme had the combined activities of alpha-amylase, cyclodextrinase, and neopullulanase. Images PMID:8206836

  12. Purification and characterization of the extracellular alpha-amylase from Streptococcus bovis JB1.

    PubMed Central

    Freer, S N

    1993-01-01

    The extracellular alpha-amylase (1,4-alpha-D-glucanglucanohydrolase; EC 3.2.1.1) from maltose-grown Streptococcus bovis JB1 was purified to apparent homogeneity by ion-exchange chromatography (Mono Q). The enzyme had an isoelectric point of 4.50 and an apparent molecular mass of 77,000 Da, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme was rich in acidic and hydrophobic amino acids. The 15-amino-acid NH2-terminal sequence was 40% homologous with the Bacillus subtilis saccharifying alpha-amylase and 27% homologous with the Clostridium acetobutylicum alpha-amylase. alpha-Amylase activity on soluble starch was optimal at pH 5.0 to 6.0. The enzyme was relatively stable between pH 5.5 and 8.5 and at temperatures below 50 degrees C. When soluble potato starch was used as the substrate, the enzyme had a Km of 0.88 mg.ml-1 and a kcat of 2,510 mumol of reducing sugar.min-1.mg of protein-1. The enzyme exhibited neither pullulanase nor dextranase activity and was 40 to 70% as active on amylopectin as on amylose. The major end products of amylose hydrolysis were maltose, maltotriose, and maltotetraose. Images PMID:8517735

  13. Validation of an assay for quantification of alpha-amylase in saliva of sheep.

    PubMed

    Fuentes-Rubio, Maria; Fuentes, Francisco; Otal, Julio; Quiles, Alberto; Hevia, María Luisa

    2016-07-01

    The objective of this study was to develop a time-resolved immunofluorometric assay (TR-IFMA) for quantification of salivary alpha-amylase in sheep. For that purpose, after the design of the assay, an analytical and a clinical validation were carried out. The analytical validation of the assay showed intra- and inter-assay coefficients of variation (CVs) of 6.1% and 10.57%, respectively and an analytical limit of detection of 0.09 ng/mL. The assay also demonstrated a high level of accuracy, as determined by linearity under dilution. For clinical validation, a model of acute stress testing was conducted to determine whether expected significant changes in alpha-amylase were picked up in the newly developed assay. In that model, 11 sheep were immobilized and confronted with a sheepdog to induce stress. Saliva samples were obtained before stress induction and 15, 30, and 60 min afterwards. Salivary cortisol was measured as a reference of stress level. The results of TR-IFMA showed a significant increase (P < 0.01) in the concentration of alpha-amylase in saliva after stress induction. The assay developed in this study could be used to measure salivary alpha-amylase in the saliva of sheep and this enzyme could be a possible noninvasive biomarker of stress in sheep. PMID:27408332

  14. ALPHA-AMYLASE ACTIVITY IN VARIOUS CONCENTRATIONS OF THE IONIC LIQUID, 1-BUTYL-3-METHYLIMIDAZOLIUM CHLORIDE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch is an extremely abundant, economical and versatile industrial commodity. Many industrial uses of starch depend on hydrolyzing the polymer for the conversion of glucose and maltodextrins. Starch hydrolysis is frequently achieved by utilizing alpha-amylase, which is an endo-acting enzyme that...

  15. Production and Partial Purification of Alpha Amylase from Bacillus subtilis (MTCC 121) Using Solid State Fermentation.

    PubMed

    Raul, Dibyangana; Biswas, Tania; Mukhopadhyay, Suchita; Kumar Das, Shrayan; Gupta, Suvroma

    2014-01-01

    Amylase is an enzyme that catalyzes the breakdown of starch into sugars and plays a pivotal role in a variety of areas like use as digestives, for the production of ethanol and high fructose corn syrup, detergents, desiring of textiles, modified starches, hydrolysis of oil-field drilling fluids, and paper recycling. In the present work, solid state fermentation (SSF) for α -amylase production has been used in lieu of submerged fermentation (SmF) due to its simple technique, low capital investment, lower levels of catabolite repression, and better product recovery. Bacillus subtilis has been well known as producer of alpha amylase and was tested using solid state fermentation for 48 hours at 37°C with wheat bran as substrate. Comparison between different fermentation hours demonstrated high yield of alpha amylase after 48 hours. This alpha amylase has optimum pH and temperature at 7.1 and 40°C, respectively. With the goal to purify alpha amylase, 30-70% (NH4)2SO4 cut concentrated the amylase activity threefold with respect to crude fermented extract. This was verified in quantitative DNS assay method as well as in zymogram gel profile. The exact molecular weight of the amylase is yet to be determined with the aid of other protein purification techniques. PMID:24672727

  16. Production of alpha-amylase from Aspergillus oryzae for several industrial applications in a single step.

    PubMed

    Porfirif, María C; Milatich, Esteban J; Farruggia, Beatriz M; Romanini, Diana

    2016-06-01

    A one-step method as a strategy of alpha-amylase concentration and purification was developed in this work. This methodology requires the use of a very low concentration of biodegradable polyelectrolyte (Eudragit(®) E-PO) and represents a low cost, fast, easy to scale up and non-polluting technology. Besides, this methodology allows recycling the polymer after precipitation. The formation of reversible soluble/insoluble complexes between alpha-amylase and the polymer Eudragit(®) E-PO was studied, and their precipitation in selected conditions was applied with bioseparation purposes. Turbidimetric assays allowed to determine the pH range where the complexes are insoluble (4.50-7.00); pH 5.50 yielded the highest turbidity of the system. The presence of NaCl (0.05M) in the medium totally dissociates the protein-polymer complexes. When the adequate concentration of polymer was added under these conditions to a liquid culture of Aspergillus oryzae, purification factors of alpha-amylase up to 7.43 and recoveries of 88% were obtained in a simple step without previous clarification. These results demonstrate that this methodology is suitable for the concentration and production of alpha-amylase from this source and could be applied at the beginning of downstream processing. PMID:27085017

  17. Increased production of alpha-amylase by Bacillus amyloliquefaciens in the presence of glycine

    SciTech Connect

    Zhang, Q.; Tsukagoshi, N.; Miyashiro, S.; Udaka, S.

    1983-07-01

    The production of alpha-amylase by Bacillus amyloliquefaciens increased by a factor of 300 when glycine was added to a chemically defined simple medium at the early-logarithmic phase of growth. Glycine was not metabolized to a significant extent under the conditions used, but it considerably prevented the lowering of the pH of the culture. (Refs. 10).

  18. Kinetic study of the irreversible thermal denaturation of Bacillus licheniformis alpha-amylase.

    PubMed Central

    Violet, M; Meunier, J C

    1989-01-01

    The irreversible thermal inactivation of Bacillus licheniformis alpha-amylase was studied. A two-step behaviour in the irreversible denaturation process was found. Our experimental results are consistent only with the two-step model and rule out the two-isoenzyme one. They suggest that the deactivation mechanism involves the existence of a temperature-dependent intermediate form. Therefore the enzyme could exist in a great number of active conformational states. We have shown that Ca2+ is necessary for the structural integrity of alpha-amylase. Indeed, dialysis against chelating agents leads to a reversible enzyme inactivation, though molecular sieving has no effect. Further, the key role of Ca2+ in the alpha-amylase thermostability is reported. The stabilizing effect of Ca2+ is reflected by the decrease of the denaturation constants of both the native and the intermediate forms. Below 75 degrees C, in the presence of 5 mM-CaCl2, alpha-amylase is completely thermostable. Neither other metal ions nor substrate have a positive effect on enzyme thermostability. The effect of temperature on the native enzyme and on one intermediate form was studied. Both forms exhibit the same optimum temperature. Identical activation parameters for the hydrolytic reaction catalysed by these two forms were found. PMID:2597125

  19. Optimization of Alpha-Amylase Application in U.S. Factories

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In recent years there have been warnings by some U.S. refineries that there may be a penalty for high starch concentrations in raw sugar if starch control is not improved. Most commercial alpha-amylases used by the U.S. sugar industry to control starch have intermediate temperature stability (up to...

  20. Peer Victimization and Aggression: Moderation by Individual Differences in Salivary Cortisol and Alpha-Amylase

    ERIC Educational Resources Information Center

    Rudolph, Karen D.; Troop-Gordon, Wendy; Granger, Douglas A.

    2010-01-01

    This research examined whether variations in salivary measures of the hypothalamic-pituitary-adrenal axis (cortisol) and autonomic nervous system (alpha amylase [sAA]) contribute to individual differences in the association between peer victimization and aggression. Children (N = 132; M age = 9.46 years, SD = 0.33) completed a measure of peer…

  1. Purification and characterization of the extracellular alpha-amylase from Streptococcus bovis JB1.

    PubMed

    Freer, S N

    1993-05-01

    The extracellular alpha-amylase (1,4-alpha-D-glucanglucanohydrolase; EC 3.2.1.1) from maltose-grown Streptococcus bovis JB1 was purified to apparent homogeneity by ion-exchange chromatography (Mono Q). The enzyme had an isoelectric point of 4.50 and an apparent molecular mass of 77,000 Da, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme was rich in acidic and hydrophobic amino acids. The 15-amino-acid NH2-terminal sequence was 40% homologous with the Bacillus subtilis saccharifying alpha-amylase and 27% homologous with the Clostridium acetobutylicum alpha-amylase. alpha-Amylase activity on soluble starch was optimal at pH 5.0 to 6.0. The enzyme was relatively stable between pH 5.5 and 8.5 and at temperatures below 50 degrees C. When soluble potato starch was used as the substrate, the enzyme had a Km of 0.88 mg.ml-1 and a kcat of 2,510 mumol of reducing sugar.min-1.mg of protein-1. The enzyme exhibited neither pullulanase nor dextranase activity and was 40 to 70% as active on amylopectin as on amylose. The major end products of amylose hydrolysis were maltose, maltotriose, and maltotetraose. PMID:8517735

  2. Phylogenetic and biochemical characterization of a novel cluster of intracellular fungal alpha-amylase enzymes.

    PubMed

    van der Kaaij, R M; Janecek, S; van der Maarel, M J E C; Dijkhuizen, L

    2007-12-01

    Currently known fungal alpha-amylases are well-characterized extracellular enzymes that are classified into glycoside hydrolase subfamily GH13_1. This study describes the identification, and phylogenetic and biochemical analysis of novel intracellular fungal alpha-amylases. The phylogenetic analysis shows that they cluster in the recently identified subfamily GH13_5 and display very low similarity to fungal alpha-amylases of family GH13_1. Homologues of these intracellular enzymes are present in the genome sequences of all filamentous fungi studied, including ascomycetes and basidiomycetes. One of the enzymes belonging to this new group, Amy1p from Histoplasma capsulatum, has recently been functionally linked to the formation of cell wall alpha-glucan. To study the biochemical characteristics of this novel cluster of alpha-amylases, we overexpressed and purified a homologue from Aspergillus niger, AmyD, and studied its activity product profile with starch and related substrates. AmyD has a relatively low hydrolysing activity on starch (2.2 U mg(-1)), producing mainly maltotriose. A possible function of these enzymes in relation to cell wall alpha-glucan synthesis is discussed. PMID:18048915

  3. Two Strategies for Microbial Production of an Industrial Enzyme-Alpha-Amylase

    NASA Technical Reports Server (NTRS)

    Bernhardsdotter, Eva C. M. J.; Garriott, Owen; Pusey, Marc L.; Ng, Joseph D.

    2003-01-01

    Extremophiles are microorganisms that thrive in, from an anthropocentric view, extreme environments including hot springs, soda lakes and arctic water. This ability of survival at extreme conditions has rendered extremophiles to be of interest in astrobiology, evolutionary biology as well as in industrial applications. Of particular interest to the biotechnology industry are the biological catalysts of the extremophiles, the extremozymes, whose unique stabilities at extreme conditions make them potential sources of novel enzymes in industrial applications. There are two major approaches to microbial enzyme production. This entails enzyme isolation directly from the natural host or creating a recombinant expression system whereby the targeted enzyme can be overexpressed in a mesophilic host. We are employing both methods in the effort to produce alpha-amylases from a hyperthermophilic archaeon (Thermococcus) isolated from a hydrothermal vent in the Atlantic Ocean, as well as from alkaliphilic bacteria (Bacillus) isolated from a soda lake in Tanzania. Alpha-amylases catalyze the hydrolysis of internal alpha-1,4-glycosidic linkages in starch to produce smaller sugars. Thermostable alpha-amylases are used in the liquefaction of starch for production of fructose and glucose syrups, whereas alpha-amylases stable at high pH have potential as detergent additives. The alpha-amylase encoding gene from Thermococcus was PCR amplified using carefully designed primers and analyzed using bioinformatics tools such as BLAST and Multiple Sequence Alignment for cloning and expression in E.coli. Four strains of Bacillus were grown in alkaline starch-enriched medium of which the culture supernatant was used as enzyme source. Amylolytic activity was detected using the starch-iodine method.

  4. Physiological characterisation of recombinant Aspergillus nidulans strains with different creA genotypes expressing A. oryzae alpha-amylase.

    PubMed

    Agger, Teit; Petersen, Jesper B; O'Connor, Susan M; Murphy, Rachael L; Kelly, Joan M; Nielsen, Jens

    2002-01-18

    The physiology of three strains of Aspergillus nidulans was examined--a creA deletion strain, a wild type creA genotype and a strain containing extra copies of the creA gene, all producing Aspergillus oryzae alpha-amylase. The strains were cultured in batch and continuous cultivations and the biomass formation and alpha-amylase production was characterised. Overexpression of the creA gene resulted in a lower maximum specific growth rate and a slightly higher repression of the alpha-amylase production during conditions with high glucose concentration. No expression of creA also resulted in a decreased maximum specific growth rate, but also in drastic changes in morphology. Furthermore, the expression of alpha-amylase was completely derepressed and creA thus seems to be the only regulatory protein responsible for glucose repression of alpha-amylase expression. The effect of different carbon sources on the alpha-amylase production in the creA deletion strain was investigated and it was found that starch was the best inducer. The degree of induction by starch increased almost linearly with the concentration of starch in starch/glucose mixtures. High-density batch cultivation was performed with the creA deletion strain and a final titre of 6.0 g l(-1) of alpha-amylase was reached after 162 h of cultivation. PMID:11689252

  5. Molecular cloning and expression of two alpha-amylase genes from Streptococcus bovis 148 in Escherichia coli.

    PubMed Central

    Satoh, E; Niimura, Y; Uchimura, T; Kozaki, M; Komagata, K

    1993-01-01

    The alpha-amylase genes of Streptococcus bovis 148 were cloned in Escherichia coli MC1061, using pBR322. The recombinant plasmids were classified into two groups on the basis of their restriction maps. Southern blot analysis did not show homology between the two types of alpha-amylase genes, and the two alpha-amylase genes existed on the chromosomal DNA of S. bovis 148. The enzymatic properties and N-terminal amino acid sequences of the two purified enzymes produced by the cloned E. coli strains were quite different from each other. Particularly, one alpha-amylase (Amy I) was adsorbed on raw corn starch and hydrolyzed raw corn starch, and another (Amy II) was not adsorbed on raw corn starch and did not hydrolyze raw corn starch. Amy I was considered to be the same as the extracellular alpha-amylase of S. bovis 148 in raw starch absorbability, ability to hydrolyze raw corn starch, enzymatic characteristics, N-terminal amino acid sequence, and mode of action on soluble starch. Amy II showed a unique pattern of oligosaccharide production from soluble starch compared with the extracellular alpha-amylase of S. bovis 148. Amy II was suggested to be an intracellular alpha-amylase of S. bovis 148. Images PMID:8285674

  6. Molecular cloning and expression of two alpha-amylase genes from Streptococcus bovis 148 in Escherichia coli.

    PubMed

    Satoh, E; Niimura, Y; Uchimura, T; Kozaki, M; Komagata, K

    1993-11-01

    The alpha-amylase genes of Streptococcus bovis 148 were cloned in Escherichia coli MC1061, using pBR322. The recombinant plasmids were classified into two groups on the basis of their restriction maps. Southern blot analysis did not show homology between the two types of alpha-amylase genes, and the two alpha-amylase genes existed on the chromosomal DNA of S. bovis 148. The enzymatic properties and N-terminal amino acid sequences of the two purified enzymes produced by the cloned E. coli strains were quite different from each other. Particularly, one alpha-amylase (Amy I) was adsorbed on raw corn starch and hydrolyzed raw corn starch, and another (Amy II) was not adsorbed on raw corn starch and did not hydrolyze raw corn starch. Amy I was considered to be the same as the extracellular alpha-amylase of S. bovis 148 in raw starch absorbability, ability to hydrolyze raw corn starch, enzymatic characteristics, N-terminal amino acid sequence, and mode of action on soluble starch. Amy II showed a unique pattern of oligosaccharide production from soluble starch compared with the extracellular alpha-amylase of S. bovis 148. Amy II was suggested to be an intracellular alpha-amylase of S. bovis 148. PMID:8285674

  7. Expression of a bacterial alpha-amylase gene in transgenic rice seeds.

    PubMed

    Xu, Xiaoli; Fang, Jun; Wang, Wei; Guo, Jianli; Chen, Pinnan; Cheng, Jiaan; Shen, Zhicheng

    2008-08-01

    An alpha-amylase gene from Bacillus stearothermophilus under the control of the promoter of a major rice-seed storage protein was introduced into rice. The transgenic line with the highest alpha-amylase activity reached about 15,000 U/g of seeds (one unit is defined as the amount of enzyme that produces 1 mumol of reducing sugar in 1 min at 70 degrees C). The enzyme produced in the seeds had an optimum pH of 5.0-5.5 and optimum temperature of 60-70 degrees C. Without extraction or purification, the power of transgenic rice seeds was able to liquify 100 times its weight of corn powder in 2 h. Thus, the transgenic rice could be used for industrial starch liquefaction. PMID:17926139

  8. Studies on alpha-amylase induced degradation of binary polymeric blends of crosslinked starch and pectin.

    PubMed

    Bajpai, A K; Shrivastava, Jyoti

    2007-05-01

    A blend matrix of crosslinked starch and pectin was prepared and characterized by infra-red (IR) spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The prepared blends were investigated kinetically for water sorption studies and alpha-amylase induced degradation adopting a gravimetric procedure. Based on the experimental findings, a plausible mechanism including both diffusion and surface enhanced degradation was suggested and degradation profiles were interpreted. The influence of various factors such as chemical architecture of the blend, pH and temperature of alpha-amylase solution were examined for the swelling and degradation kinetics of crosslinked starch-pectin blends. The effect of concentration of enzyme solution was also studied on the degradation profile of the blends. A correlation was established between the extent of degradation and water imbibing capacity of the degrading blends. PMID:17143735

  9. Convenience of immobilized Bacillus licheniformis alpha-amylase as time-temperature-integrator (TTI).

    PubMed

    De Cordt, S F; Hendrickx, M E; Maesmans, G J; Tobback, P P

    1994-02-01

    For the immobilization of Bacillus licheniformis alpha-amylase to porous glass beads, the performances of three possible linking agents, glutaric dialdehyde, benzoquinone and s-trichlorotriazine were assessed in respect of the protein yield, the enzymic activity and the thermostability of the immobilized enzyme. These three properties are to be evaluated in view of the possible use of the enzyme preparations as time-temperature-integrators (TTIs) for assessing the severity of heat pasteurization or sterilization processes of food or pharmaceuticals. All three linkers improved the enzyme's resistance to irreversible heat inactivation to a similar extent and in each case biphasic inactivation kinetics were observed, whereas the dissolved B. licheniformis alpha-amylase showed a simple first order decay. The immobilization yield, measured as protein per carrier weight, did not differ markedly for the three linkers, although the enzymic activity of the glutaric dialdehyde-linked enzyme was lower than that of the benzoquinone- and s-trichlorotriazine-linked preparations. PMID:7764538

  10. Production and characterization of a thermostable alpha-amylase from Nocardiopsis sp. endophyte of yam bean.

    PubMed

    Stamford, T L; Stamford, N P; Coelho, L C; Araújo, J M

    2001-01-01

    Thermostable amylolytic enzymes have been currently investigated to improve industrial processes of starch degradation. Studies on production of alpha-amylase by Nocardiopsis sp., an endophytic actinomycete isolated from yam bean (Pachyrhizus erosus L. Urban), showed that higher enzyme levels were obtained at the end of the logarithmic growth phase after incubation for 72 h at pH 8.6. Maximum activity of alpha-amylase was obtained at pH 5.0 and 70 degrees C. The isolated enzyme exhibited thermostable properties as indicated by retention of 100% of residual activity at 70 degrees C, and 50% of residual activity at 90 degrees C for 10 min. Extracellular enzyme from Nocardiopsis sp. was purified by fractional precipitation with ammonium sulphate. After 60% saturation produced 1130 U mg-1 protein and yield was 28% with purification 2.7-fold. The enzyme produced by Nocardiopsis sp. has potential for industrial applications. PMID:11131797

  11. Alpha-amylase circadian rhythm of young rat parotid gland: an endogenous rhythm with maternal coordination.

    PubMed

    Bellavía, S L; Sanz, E G; Sereno, R; Vermouth, N T

    1992-01-01

    The circadian rhythm of alpha-amylase, E.C. 3.2.1.1. alpha-1,4-glucan-4-glucanohydrolase) in the parotid glands of 25-day-old rats were studied under different experimental designs (fasting, reversed photoperiod, constant lighting conditions and treatment with reserpine and alpha-methyl-p-tyrosine). The rhythm of fasted rats did not change. There were modifications in the rhythm of rats submitted to a reversed photoperiod or treated with reserpine or alpha-methyl-p-tyrosine. The rhythm was present, with changes in the acrophase, in parotids of rats kept during their gestation and postnatal life in constant light or dark. Results suggest that the circadian rhythm of alpha-amylase in parotid gland of young rats is endogenous, synchronized by the photoperiod, and with maternal coordination. PMID:1610312

  12. Ontogenesis of alpha-amylase in rat parotid gland during postnatal development.

    PubMed

    Bellavia, S L; Sanz, E G; Vermouth, N T; Rins, L; Aoki, A

    1981-01-01

    Changes in alpha-amylase (alpha-1,4-glucan-4-glucanohydrolase, EC 3.2.1.1) of parotid gland were investigated during postnatal development of the rat. Modifications in amylase activity after birth allow the distinction of three stages which can be correlated with the morphologic development of the parotid gland. Significant sexual differences in the evolution of alpha-amylase activity were found. During the first stage (from birth to the 20th day) there is a higher increase in females, while males have a more pronounced increment in the second stage (from the 20th to the 30th day). By means of gel electrophoresis of parotid extracts, four molecular forms of amylase can be separated. The slowest migrating band (Form 1) is not detected at the initial stage. PMID:6164673

  13. Expression and secretion of alpha-amylase and glucoamylase in Saccharomyces cerevisiae.

    PubMed

    Luo, J; He, M; Li, W; Zhang, T

    1994-01-01

    alpha-Amylase genes of Bacillus licheniformis and glucoamylase cDNA of Aspergillus niger were ligated to a E. coli-yeast shuttle vector. The resultant plasmid was used to transform Saccharomyces cerevisiae to construct starch-degrading yeast strain. The results of enzyme activity assay and enzyme property analysis show that alpha-amylase and glucoamylase genes have been expressed simultaneously in yeast under the control of promoters and terminators of yeast MF-alpha 1 factor and PGK genes and over 99% of enzyme activities were secreted to the medium. The engineered yeast strain hydrolyses 97% of the starch (10%) in the medium after 6 days. The recombinant plasmid exists stably in yeast. PMID:7780020

  14. Polymorphism of salivary esterase and alpha-amylase in the Greek population.

    PubMed

    Petalopoulos, A; Fousteri, M; Kouvatsi, A; Triantaphyllidis, C

    1993-01-01

    The genetic polymorphism of two salivary enzymes (esterase and alpha-amylase) was studied in individuals from eight districts of Greece. The pooled gene frequencies were: SetS = 0.63, SetF = 0.37, AMY1 = 0.87, AMY2 = 0.10, AMY3 = 0.02, and AMY4 = 0.01. There was no intrapopulation heterogeneity, while there was a significant difference between the Greeks and the few other European populations studied. PMID:7507080

  15. The genetic control of the alpha-amylase isozymes of the durum wheat (Triticum durum Desf.).

    PubMed

    Prokopyk, D O; Antonyuk, M Z; Ternovskaya, T K

    2009-01-01

    The hybridological analysis was provided on several durum wheat genotypes with utilizing three F2 populations developed from the crossing between parental forms that differed in the invariable malt-zone triplet on electrophoretic spectrum of alpha-amylase. Three components of this zone are controlled by three genes with an independent way of inheritance: one of them is located on the 6B or 5B chromosome, and two genes are located on the chromosomes of A subgenome. PMID:19938630

  16. Statistical media optimization and production of ITS alpha-amylase from Aspergillus oryzae in a bioreactor.

    PubMed

    Gigras, Paresh; Sahai, Vikram; Gupta, Rani

    2002-09-01

    The production of an intermediate temperature-stable (ITS) alpha-amylase from Aspergillus oryzae was studied by using a central composite design with three independent variables, viz., starch, yeast extract, and K(2)HPO(4). The model equation provided a suitable model for the response surface for alpha-amylase production, and, from the optimal concentrations of the medium components, a model was predicted, which was then used for enzyme production in a 150-L bioreactor. In the bioreactor studies, the enzyme yields (161 U/ml) were similar to that of the shake flask (133 U/ml); however, the time required for maximum alpha-amylase production in the bioreactor was reduced to 48 h compared with 120 h in shake flask cultures. An increased level of phosphate in the medium and low inoculum size were necessary to control the excessive foaming in the bioreactor; however, control of the pO(2) level and agitation was not mandatory for enzyme production. The peak enzyme production coincided with the increase in pH of the fermentation broth and was maximal when the pH of the system was above 7.5. Thus, in the present study, pH acted as an indicator of the initiation or end of the enzyme synthesis or of the fermentation cycle. PMID:12177743

  17. Coconut oil cake--a potential raw material for the production of alpha-amylase.

    PubMed

    Ramachandran, Sumitra; Patel, Anil K; Nampoothiri, K Madhavan; Francis, Febe; Nagy, Viviana; Szakacs, George; Pandey, Ashok

    2004-06-01

    Solid-state fermentation (SSF) was carried out using coconut oil cake (COC) as substrate for the production of alpha-amylase using a fungal culture of Aspergillus oryzae. Raw COC supported the growth of the culture, resulting in the production of 1372 U/gds alpha-amylase in 24 h. Process optimization using a single parameter mode showed enhanced enzyme titre, which was maximum (1827 U/gds) when SSF was carried out at 30 degrees C for 72 h using a substrate with 68% initial moisture. Supplementation with glucose and starch further enhanced enzyme titre, which was maximum (1911 U/gds) with 0.5% starch. However, maltose inhibited the enzyme production. Studies on the effect of addition of external organic and inorganic nitrogenous compounds further showed a positive impact on enzyme synthesis by the culture. Increase of 1.7-fold in the enzyme activity (3388 U/gds) was obtained when peptone at 1% concentration was added to the fermentation medium. The enzyme production was growth-related, the activity being the maximum when the fungal biomass was at its peak at 72 h. Use of COC as raw material for enzyme synthesis could be of great commercial significance. To the best of our knowledge this is the first report on alpha-amylase production using COC in SSF. PMID:15051078

  18. Production and properties of alpha-amylase from Penicillium chrysogenum and its application in starch hydrolysis.

    PubMed

    Balkan, Bilal; Ertan, Figen

    2005-01-01

    Fungi were screened for their ability to produce alpha-amylase by a plate culture method. Penicillium chrysogenum showed high enzymatic activity. Alpha-amylase production by P. chrysogenum cultivated in liquid media containing maltose (2%) reached its maximum at 6-8 days, at 30 degrees C, with a level of 155 U ml(-1). Some general properties of the enzyme were investigated. The optimum reaction pH and temperature were 5.0 and 30-40 degrees C, respectively. The enzyme was stable at a pH range from 5.0-6.0 and at 30 degrees C for 20 min and the enzyme's 92.1% activity's was retained at 40 degrees C for 20 min without substrate. Hydrolysis products of the enzyme were maltose, unidefined oligosaccharides, and a trace amount of glucose. Alpha-amylase of P. chrysogenum hydrolysed starches from different sources. The best hydrolysis was determined (98.69%) in soluble starch for 15 minute at 30 degrees C. PMID:15881598

  19. Starch-binding domain affects catalysis in two Lactobacillus alpha-amylases.

    PubMed

    Rodríguez-Sanoja, R; Ruiz, B; Guyot, J P; Sanchez, S

    2005-01-01

    A new starch-binding domain (SBD) was recently described in alpha-amylases from three lactobacilli (Lactobacillus amylovorus, Lactobacillus plantarum, and Lactobacillus manihotivorans). Usually, the SBD is formed by 100 amino acids, but the SBD sequences of the mentioned lactobacillus alpha-amylases consist of almost 500 amino acids that are organized in tandem repeats. The three lactobacillus amylase genes share more than 98% sequence identity. In spite of this identity, the SBD structures seem to be quite different. To investigate whether the observed differences in the SBDs have an effect on the hydrolytic capability of the enzymes, a kinetic study of L. amylovorus and L. plantarum amylases was developed, with both enzymes acting on several starch sources in granular and gelatinized forms. Results showed that the amylolytic capacities of these enzymes are quite different; the L. amylovorus alpha-amylase is, on average, 10 times more efficient than the L. plantarum enzyme in hydrolyzing all the tested polymeric starches, with only a minor difference in the adsorption capacities. PMID:15640201

  20. Ontogeny of alpha-amylase circadian rhythms in rat parotid gland.

    PubMed

    Sanz, E G; Vermouth, N T; Bellavia, S L

    1986-01-01

    The content of alpha-amylase (alpha-1,4-glucan-4-glucanohydrolase, EC 3.2.1.1.) and total soluble proteins of parotid glands (from rats exposed to a photoperiod of 14 hr light: 10 hr dark), have been determined every 2 or 3 hr over 24 hr periods in 15, 25 and 90-day-old rats. In 35-, 45- and 72-day-old rats, determinations were performed only at 0100 and 1400 hr. The alpha-amylase and total soluble protein contents from 90-day-old rats show a circadian variation, with a maximum value at 2200 hr and a minimum at 1400 hr. Parotids from 15- and 25-day-old rats also show a circadian rhythm. The minimum value is recorded at 0100 hr and the maximum at 1400 hr. At day 35 and after, there is an inversion of the amylase rhythm. In immature rats, it appears that alpha-amylase and soluble protein are under the influence of another synchronizer, whose timing is independent of that imposed by mastication of solid food. PMID:2878787

  1. [Influence of amaranth on the production of alpha-amylase using Aspergillus niger NRRL 3112].

    PubMed

    Mariani, D D; Lorda, G; Balatti, A P

    2000-01-01

    In this paper the influence of the amaranth seed meal and the aeration conditions on the alpha-amylase production by Aspergillus niger NRRL 3112 were studied. The assays of selection of culture medium were carried out in a rotary shaker at 250 rpm and 2.5 cm stroke. The aeration conditions were studied in a mechanically stirred fermentor New Brunswick type. A concentration of alpha-amylase of 2750 U.Dun/ml was achieved at 120 h with a dry weight of 8.0 g/l, using a base medium with 5.0 g/l Amaranthus cruentus seed meal. In the experiment performed in a New Brunswick fermentor, the highest value was 2806 U.Dun/ml. This result was obtained after 120 h, operating at 300 rpm and an airflow of 1 l/l. min. in a limited dissolved oxygen concentration. It was determined that the increase in the agitation rate was not favorable to the enzyme production, despite that an increase was verified in the dissolved oxygen. The morphology of the microorganism, in long and ramified hyphae, was the critical factor to obtain higher levels of alpha-amylase. PMID:11149149

  2. Grain Development Mutants of Barley ([alpha]-Amylase Production during Grain Maturation and Its Relation to Endogenous Gibberellic Acid Content).

    PubMed Central

    Green, L. S.; Faergestad, E. M.; Poole, A.; Chandler, P. M.

    1997-01-01

    Barley (Hordeum vulgare L. Himalaya) mutants with altered grain morphology were isolated to investigate whether defects in grain development, possibly involving gibberellins (GAs) and abscisic acid, would lead to altered patterns of [alpha]-amylase gene expression. Following treatment with sodium azide, 75 mutants, typically showing grain shriveling, were identified. At grain maturity 15 of the 75 mutants had higher [alpha]-amylase activities in shriveled grains compared with either phenotypically normal grains that developed on the same heterozygous plant or with grains of cv Himalaya. Studies of four of these mutants demonstrated increased levels of both high- and low-isoelectric point [alpha]-amylase isozymes midway through grain development. This category of mutant has been designated pga, for premature grain [alpha]-amylase. One such mutant (M326) showed an endosperm-determined inheritance pattern. When crossed into a (GA-deficient) dwarfing background there was a 10- to 20-fold reduction in [alpha]-amylase activity, suggesting a requirement for GA biosynthesis. Endogenous GAs and abscisic acid were quantified by combined gas chromatography-specific ion monitoring in normal and mutant grains of heterozygous M326 plants during the period of [alpha]-amylase accumulation. Mutant grains had significantly higher (5.8-fold) levels of the bioactive GA1 compared with normal grains but much lower (approximately 10-fold) levels of the 2[beta]-hydroxylated ("inactive") GAs, typical of developing barley grains (e.g. GA8, GA34, GA48). We propose that a reduced extent of 2[beta]-hydroxylation in the mutant grains results in an increased level of GA1, which is responsible for premature [alpha]-amylase gene expression. PMID:12223700

  3. In vitro and in vivo inhibition of alpha-amylases of stored-product mite Acarus siro.

    PubMed

    Hubert, Jan; Dolecková-Maresová, Lucie; Hýblová, Jana; Kudlíková, Iva; Stejskal, Václav; Mares, Michael

    2005-01-01

    The stored-product mites are the most abundant and frequent group of pests living on the stored food products in Europe. They endanger public health since they produce allergens and transmit mycotoxin-producing fungi. Novel acaricidal compounds with inhibitory effects on the digestive enzymes of arthropods are a safe alternative to the traditional neurotoxic pesticides used for control of the stored-product pests. In this work, we explored the properties of acarbose, the low molecular weight inhibitor of alpha-amylases (AI), as a novel acaricide candidate for protection of the stored products from infestation by Acarus siro (Acari: Acaridae). In vitro analysis revealed that AI blocked efficiently the enzymatic activity of digestive amylases of A. siro, and decreased the physiological capacity of mite's gut in utilizing a starch component of grain flour. In vivo experiments showed that AI suppressed the population growth of A. siro. The mites were kept for three weeks on experimental diet enriched by AI in concentration range of 0.005 to 0.25%. Population growth of A. siro was negatively correlated with the content of AI in the treated diet with a half-population dose of 0.125%. The suppressive effect of AIs on stored-product mites is discussed in the context of their potential application in GMO crops. PMID:15969461

  4. Secretion, purification, and characterisation of barley alpha-amylase produced by heterologous gene expression in Aspergillus niger.

    PubMed

    Juge, N; Svensson, B; Williamson, G

    1998-04-01

    Efficient production of recombinant barley alpha-amylase has been achieved in Aspergillus niger. The cDNA encoding alpha-amylase isozyme 1 (AMY1) and its signal peptide was placed under the control of the Aspergillus nidulans glyceraldehyde-3-phosphate dehydrogenase (gpd) promoter and the A. nidulans trpC gene terminator. Secretion yields up to 60 mg/l were obtained in media optimised for alpha-amylase activity and low protease activity. The recombinant AMY1 (reAMY1) was purified to homogeneity and found to be identical to native barley AMY1 with respect to size, pI, and immunoreactivity. N-terminal sequence analysis of the recombinant protein indicated that the endogenous plant signal peptide is correctly processed in A. niger. Electrospray ionisation/mass spectrometry gave a molecular mass for the dominant form of 44,960 Da, in accordance with the loss of the LQRS C-terminal residues; glycosylation apparently did not occur. The activities of recombinant and native barley alpha-amylases are very similar towards insoluble and soluble starch as well as 2-chloro-4-nitrophenol beta-D-maltoheptaoside and amylose (degree of polymerisation = 17). Barley alpha-amylase is the first plant protein efficiently secreted and correctly processed by A. niger using its own signal sequence. PMID:9615479

  5. A Proposed Mechanism for the Thermal Denaturation of a Recombinant Bacillus Halmapalus Alpha-amylase - the Effect of Calcium Ions

    NASA Technical Reports Server (NTRS)

    Nielsen, Anders D.; Pusey, Marc L.; Fuglsang, Claus C.; Westh, Peter

    2003-01-01

    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 previous crystallographic studies have identified the existence of 3 calcium binding sites in the structure. Denaturation of BHA is irreversible with a Tm of approximately 89 C, and DSC thermograms can be described using a one-step irreversible model. A 5 C increase in T(sub m) in the presence of 10 fold excess CaCl2 was observed. However, a concomitant increase in the tendency to aggregate was also observed. The presence of 30-40 fold excess calcium chelator (EDTA or EGTA) results in a large destabilization of BHA corresponding to about 40 C lower T(sub m), as determined by both CD and DSC. Ten fold excess EGTA reveals complex DSC thermograms corresponding to both reversible and irreversible transitions, which possibly originate from different populations of BHA:calcium complexes. The observations in the present study have, in combination with structural information of homologous alpha-amylases, provided the basis for the proposal of a simple denaturation mechanism of BHA. The proposed mechanism describes the irreversible thermal denaturation of different BHA:calcium complexes and the calcium binding equilibrium involved. Furthermore, the model accounts for a temperature induced reversible structural change associated with calcium binding.

  6. Alpha-amylase inhibitory activity and phytochemical study of Zhumeria majdae Rech. f. and Wendelbo

    PubMed Central

    Mirshafie, Behnaz; Mokhber-Dezfouli, Najmeh; Manayi, Azadeh; Saeidnia, Soodabeh; Ajani, Yousef; Gohari, Ahmad Reza

    2015-01-01

    Background: Zhumeria majdae (Lamiaceae) is an endemic species growing in the South parts of Iran especially Hormozgan province. The plant is so-called Mohrekhosh locally and widely used for medicinal purposes including stomachache and dysmenorrhea. Objective: In order to separation and identification of the main flavonoid glycosides of the plant (aerial parts including leaves, stems, flowers, and fruits were used) and evaluation of its alpha-amylase inhibitory (AAI) activity, methanolic extract was prepared and fractionated to botanolic portion. Materials and Methods: Isolation of the main compounds of the butanol extract of the plant have been performed using different column chromatography methods such as high-performance liquid chromatography (C18 column) and Sephadex LH-20 as well. The isolated compounds were identified by Hydrogen-1 nuclear magnetic resonance and Carbon-13 nuclear magnetic resonance spectra and comparison with those reported in previous literature. Moreover, inhibitory activity of the butanolic extract of the plant against alpha-amylase enzyme was examined in different concentrations (15–30 mg/mL), where acarbose used as a positive control. Results: Three flavonoid glycosides: Linarin (1), hispidulin-7-O-(4-O-acetyl-rutinoside) (2), hispidulin-7-O-rutinoside (3) were successfully identified in the extract. The activity of alpha amylase enzyme was dose-dependently suppressed by the butanol extract. The extract exhibited the highest inhibition at 30 mg/mL toward enzyme (77.9 ± 2.1%), while acarbose inhibited the enzyme at 20 mg/mL by 73.9 ± 1.9%. The inhibitory concentrations of 50% for the extract and acarbose were calculated at 24.5 ± 2.1 and 6.6 ± 3.1 mg/mL, respectively. Conclusion: Z. majdae contains glycosylated flavones and could be a good candidate for anti-diabetic evaluations in animal and clinical trials due to possessing AAI activity. PMID:26692743

  7. Purification by expanded bed adsorption and characterization of an alpha-amylases FORILASE NTL from A. niger.

    PubMed

    Toledo, A L; Severo, J B; Souza, R R; Campos, E S; Santana, J C C; Tambourgi, E B

    2007-02-01

    In this work the purification and biochemistry characterization of alpha-amylases from Aspergillus niger (FORILASE NTL) were studied. The effects of expansion degree of resin bed on enzyme purification by expanded bed adsorption (EBA) have also been studied. Residence time distributions (RTD) studies were done to achieve the optimal conditions of the amylases recovery on ion-exchange resin, and glucose solution was used as a new tracer. Results showed that height equivalent of the theoretical plates (HETP), axial dispersion and the Prandt number increased with bed height, bed voidage and linear velocity. The adsorption capacity of alpha-amylases, on the resin, increased with bed height and the best condition was at four-expansion degree. alpha-Amylase characterization showed that this enzyme has high affinity with soluble starch, good hydrolysis potential and molecular weight of 116 kDa. PMID:16959553

  8. Characteristics of alpha-Amylase during Germination of Two High-Sugar Sweet Corn Cultivars of Zea mays L.

    PubMed

    Sanwo, M M; Demason, D A

    1992-07-01

    The role of the scutellum and the aleurone in alpha-amylase production in the high-sugar sweet corn cultivars Illini X-tra Sweet (shrunken-2, sh2) and Illinois 677a (sugary, sugary enhancer; su se) was compared to that in the starchy (Su) hybrid Funks G4646 with the use of alpha-amylase enzyme assays, isoelectric focusing, electron microscopy, and laser scanning confocal microscopy. The scutellum of Illinois 677a had low levels of alpha-amylase activity compared to that of Funks G4646 through 10 days after imbibition, and the aleurone of Illini X-tra Sweet had negligible activity. On the isoelectric focusing gels, the Illinois 677a scutellum had fewer alpha-amylase isozymes at 7 days compared to the Funks G4646 scutellum. The Illini X-tra Sweet aleurone had no alpha-amylase isozymes. Funks G4646 scutellar epithelial and aleurone cells contained abundant rough endoplasmic reticulum, polysomes, and dictyosomes at 5 and 7 days, respectively. The scutellar epithelial cells of Illinois 677a contained fewer of these structures by 5 days, and the Illini X-tra Sweet aleurone contained mostly lipid bodies through 7 days. Few cytoplasmic membranes and little RNA were detected with laser scanning confocal microscopy in the Illini X-tra Sweet aleurone compared to Funks G4646 at 7 days. These data suggest that the scutellum of Illinois 677a and the aleurone of Illini X-tra Sweet have impaired abilities to produce alpha-amylase. PMID:16668987

  9. Isolation and Partial Characterization of a Factor from Barley Aleurone that Modifies alpha-Amylase in Vitro.

    PubMed

    Sticher, L; Jones, R L

    1991-11-01

    Posttranslational modifications that give rise to multiple forms of alpha-amylase (EC 3.2.1.1) in barley (Hordeum vulgare L. cv Himalaya) were studied. When analyzed by denaturing polyacrylamide gel electrophoresis, barley alpha-amylase has a molecular mass of 43 to 44 kilodaltons, but isoelectric focusing resolves the enzyme into a large number of isoforms. To precisely identify these isoforms, we propose a system of classification based on their isoelectric points (pl). alpha-Amylases with pls of approximately 5, previously referred to as low pl or Amy1 isoforms, have been designated HAMY1, and alpha-amylases with pls of approximately 6, referred to as high pl or Amy2, are designated HAMY2. Individual isoforms of HAMY1 and HAMY2 are identified by their pls. For example, the most acidic alpha-amylase synthesized and secreted by barley aleurone layers is designated HAMY1(4.56). Some of the diversity in the pls of barley alpha-amylases arises from posttranslational modifications of the enzyme. We report the isolation of a factor from barley aleurone layers and incubation media that can modify HAMY1 isoforms in vitro. This factor has a molecular mass between 30 and 50 kilodaltons, and it can catalyze the conversion of HAMY1(4.90) and HAMY1(4.64) to isoforms 4.72 and 4.56, respectively. The in vitro conversion of HAMY1 isoforms by the factor is favored by pH values of approximately 5 and is inhibited at approximately pH 7. The level of this factor in aleurone layers and incubation media is not affected by treatment of the tissue with gibberellic acid. The amylase-modifying activity from barley will also modify alpha-amylases isolated from human saliva and porcine pancreas. An activity that can modify HAMY1 isoforms in vitro has also been isolated from Onozuka R10 cellulase. Because the activity isolated from barley lowers the pl of alpha-amylase from barley, human saliva, and porcine pancreas, we speculate that it is a deamidase. PMID:16668534

  10. Stable yeast transformants that secrete functional. cap alpha. -amylase encoded by cloned mouse pancreatic cDNA

    SciTech Connect

    Filho, S.A.; Galembeck, E.V.; Faria, J.B.; Frascino, A.C.S.

    1986-04-01

    Mouse pancreatic ..cap alpha..-amylase complementary DNA was inserted into a yeast shuttle vector after the Saccharomyces cerevisiae MF..cap alpha..1 promoter and secretion signals coding sequences. When transformed with the recombinant plasmid, S. cerevisiae cells were able to synthesize and secrete functional ..cap alpha..-amylase, efficiently hydrolyzing starch present in the culture medium. Stable amylolytic cells were obtained from different yeast strains. This work represents a significant step towards producing yeast that can convert starchy materials directly to ethanol.

  11. Dual feeding strategy for the production of alpha-amylase by Bacillus caldolyticus using complex media.

    PubMed

    Schwab, Karima; Bader, Johannes; Brokamp, Christian; Popović, Milan K; Bajpai, Rakesh; Berovic, Marin

    2009-10-01

    In this study, the objective was to investigate an exponential feeding strategy for fed-batch production of thermostable alpha-amylase (E.C. 3.2.1.1.) from the Bacillus caldolyticus (DSM405). The parameters for establishing compositions of feed media and feeding rate were obtained by statistical analysis of batch and continuous shake flask experiments. These parameters were casitone to starch ratio of 2.67g(casitone)g(starch)(-1), maintenance coefficient 0.174g(casitone)g(DW)(-1)h(-1), cell yield 0.62g(DW)g(casitone)(-1) and mu(opt)=0.2h(-1). The exponentially fed fermentation resulted in yield of 120Uml(-1) alpha-amylase that was thermostable up to 105 degrees C. Results of the exponentially fed fermentation have been discussed in the light of a feed-back controlled fed-batch fermentation reported earlier by the authors. A comparison of the temperature and pH effects on amylase produced by B. caldolyticus and on several other commercially available amylases has also been presented. PMID:19439206

  12. Cloning and characterization of a third type of human alpha-amylase gene, AMY2B.

    PubMed

    Yokouchi, H; Horii, A; Emi, M; Tomita, N; Doi, S; Ogawa, M; Mori, T; Matsubara, K

    1990-06-15

    We have previously reported concerning the existence of a third type of human alpha-amylase gene, AMY3 [Emi et al., Gene 62 (1988) 229-235; Tomita et al., Gene 76 (1989) 11-18], which is expressed in a lung carcinoid tissue, and differs in nucleotide sequence from the two previously characterized human alpha-amylase genes coding for salivary and pancreatic isozymes, termed AMY1 and AMY2, respectively. Here, we rename this gene AMY2B to coincide with the designation by Gumucio et al. [Mol. Cell Biol. 8 (1988) 1197-1205] and describe its genetic properties as revealed by sequencing studies. It consists of ten major exons whose sequences are highly homologous to those of AMY1 and AMY2. Not only the exons, but also most of the introns seem to be highly conserved, as judged from physical mapping data. The AMY2B gene identified from mRNA in a lung carcinoid tissue has at least two additional untranslated exons in its 5' region; hence the promoter lies far upstream relative to the other two AMY genes. PMID:2401405

  13. Cortisol, salivary alpha-amylase and children's perceptions of their social networks.

    PubMed

    Ponzi, Davide; Muehlenbein, Michael P; Geary, David C; Flinn, Mark V

    2016-04-01

    In recent years there has been a growing interest in the use of social network analysis in biobehavioral research. Despite the well-established importance of social relationships in influencing human behavior and health, little is known about how children's perception of their immediate social relationships correlates with biological parameters of stress. In this study we explore the association between two measures of children's personal social networks, perceived network size and perceived network density, with two biomarkers of stress, cortisol and salivary alpha-amylase. Forty children (mean age = 8.30, min age = 5, and max age = 12) were interviewed to collect information about their friendships and three samples of saliva were collected. Our results show that children characterized by a lower pre-interview cortisol concentration and a lower salivary alpha-amylase reactivity to the interview reported the highest density of friendships. We discuss this result in light of the multisystem approach to the study of children's behavioral outcomes, emphasizing that future work of this kind is needed in order to understand the cognitive and biological mechanisms underlying children's and adolescents' social perceptual biases. PMID:25919481

  14. Cloning, characterization, and expression of two alpha-amylase genes from Aspergillus niger var. awamori.

    PubMed

    Korman, D R; Bayliss, F T; Barnett, C C; Carmona, C L; Kodama, K H; Royer, T J; Thompson, S A; Ward, M; Wilson, L J; Berka, R M

    1990-03-01

    Using synthetic oligonucleotide probes, we cloned genomic DNA sequences encoding an alpha-amylase gene from Aspergillus niger var. awamori (A. awamori) on a 5.8 kb EcoRI fragment. Hybridization experiments, using a portion of this cloned fragment to probe DNA from A. awamori, suggested the presence of two alpha-amylase gene copies which were subsequently cloned as 7 kb (designated as amyA) and 4 kb (amyB) HindIII fragments. DNA sequence analysis of the amyA and amyB genes revealed the following: (1) Both genes are arranged as nine exons and eight introns; (2) The nucleotide sequences of amyA and amyB are identical throughout all but the last few nucleotides of their respective coding regions; (3) The amyA and amyB genes from A. awamori share extensive homology (greater than or equal to 98% identity) with the genes encoding Taka-amylase from A. oryzae. In order to test whether both amyA and amyB were functional in the genome, we constructed vectors containing gene fusions of either amyA and amyB to bovine prochymosin cDNA and used these vectors to transform A. awamori. Transformants which contained either the amyA- or amyB-prochymosin gene fusions produced extracellular chymosin, suggesting that both genes are functional. PMID:2340591

  15. Effect of neohesperidin dihydrochalcone on the activity and stability of alpha-amylase: a comparative study on bacterial, fungal, and mammalian enzymes.

    PubMed

    Kashani-Amin, Elaheh; Ebrahim-Habibi, Azadeh; Larijani, Bagher; Moosavi-Movahedi, Ali Akbar

    2015-10-01

    Neohesperidin dihydrochalcone (NHDC) was recently introduced as an activator of mammalian alpha-amylase. In the current study, the effect of NHDC has been investigated on bacterial and fungal alpha-amylases. Enzyme assays and kinetic analysis demonstrated the capability of NHDC to significantly activate both tested alpha-amylases. The ligand activation pattern was found to be more similar between the fungal and mammalian enzyme in comparison with the bacterial one. Further, thermostability experiments indicated a stability increase in the presence of NHDC for the bacterial enzyme. In silico (docking) test locates a putative binding site for NHDC on alpha-amylase surface in domain B. This domain shows differences in various alpha-amylase types, and the different behavior of the ligand toward the studied enzymes may be attributed to this fact. PMID:25808616

  16. 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.

    PubMed

    Ajandouz, E H; Abe, J; Svensson, B; Marchis-Mouren, G

    1992-09-23

    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. PMID:1390923

  17. A single gene directs synthesis of a precursor protein with beta- and alpha-amylase activities in Bacillus polymyxa.

    PubMed Central

    Uozumi, N; Sakurai, K; Sasaki, T; Takekawa, S; Yamagata, H; Tsukagoshi, N; Udaka, S

    1989-01-01

    The Bacillus polymyxa amylase gene comprises 3,588 nucleotides. The mature amylase comprises 1,161 amino acids with a molecular weight of 127,314. The gene appeared to be divided into two portions by the direct-repeat sequence located at almost the middle of the gene. The 5' region upstream of the direct-repeat sequence was shown to be responsible for the synthesis of beta-amylase. The 3' region downstream of the direct-repeat sequence contained four sequences homologous with those in other alpha-amylases, such as Taka-amylase A. The 48-kilodalton (kDa) amylase isolated from B. polymyxa was proven to have alpha-amylase activity. The amino acid sequences of the peptides generated from the 48-kDa amylase showed complete agreement with the predicted amino acid sequence of the C-terminal portion. The B. polymyxa amylase gene was therefore concluded to contain in-phase beta- and alpha-amylase-coding sequences in the 5' and 3' regions, respectively. A precursor protein, a 130-kDa amylase, directed by a plasmid, pYN520, carrying the entire amylase gene, had both beta- and alpha-amylase activities. This represents the first report of a single protein precursor in procaryotes that gives rise to two enzymes. Images PMID:2464578

  18. Permissive role of the acidification caused by wheat aleurone layers upon. alpha. -amylase induction by GA sub 3

    SciTech Connect

    Rodriguez-Campos, E.; Bernal-Lugo, I.; Hamabata, A. )

    1989-04-01

    Wheat aleurone has the capacity of acidifying the incubation medium in 1 to 2 pH units. The {alpha}-amylase induction by GA{sub 3} in isolated wheat aleurone layers is strongly dependent on acidic pH of the medium (pH < 5). To examine possible mechanisms {sup 35}-Met incorporation into proteins and {alpha}-amylase, in the presence of GA{sub 3} and Ca{sup 2+} at pH, 4, 5 and 6 was studied. Although {sup 35}-Met uptake decreased markedly ({approx} 90%) at pH 4 in thepresence of GA{sub 3}, incorporation into total protein did not change significantly from other conditions. Auto-radiography of SDS-PAGE showed that most of the amino acid was in the {alpha}-amylase band, meaning that the effect of acidic pH is specific for GA{sub 3} actions on aleurone tissue. On the other hand, an increase of protonated GA{sub 3} diffusion could be ruled out. Also, there was not {alpha}-amylase inactivation at pH 6. These findings point out to the important physiological role of the acidification caused by the aleurone.

  19. Maltose effects on barley malt diastatic power enzyme activity and thermostability at high isothermal mashing temperature: II. Alpha-amylase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maltose, the primary product of starch degradation during mashing, has the potential as a compatible solute to affect the activity of and increase the thermostability of barley malt alpha-amylase activity at high temperatures used in mashing and temperatures above those normally used in mashing. To ...

  20. Daytime Secretion of Salivary Cortisol and Alpha-Amylase in Preschool-Aged Children with Autism and Typically Developing Children

    ERIC Educational Resources Information Center

    Kidd, Sharon A.; Corbett, Blythe A.; Granger, Douglas A.; Boyce, W. Thomas; Anders, Thomas F.; Tager, Ira B.

    2012-01-01

    We examined daytime salivary cortisol and salivary alpha-amylase (sAA) secretion levels and variability in preschool-aged children with autism (AUT) and typically developing children (TYP). Fifty-two subjects (26 AUT and 26 TYP) were enrolled. Salivary samples were obtained at waking, midday, and bedtime on two consecutive days at three phases…

  1. Effects of metals on {alpha}-amylase activity in the digestive gland of the green mussel, Perna viridis L.

    SciTech Connect

    Yan, T.; Teo, L.H.; Sin, Y.M.

    1996-04-01

    A number of digestive enzymes in the green mussel, Perna viridis L., have been reported, and {alpha}-amylase is believed to have a higher activity than the others. Small plankton, on which the green mussel feeds, may supply plenty of starch and glycogen. They may be an important source of nutrients for the green mussel and the ability of the latter to make good use of them depends mainly on the activities of amylase. The effect of heavy metals on amylase activity is also important as the ability of the mussel`s digestive gland to accumulate these metals is well known. High concentrations of heavy metals, especially lead, have been observed in the water around Singapore. The in vitro inhibition of some metals on the activities of digestive enzymes from the green mussel has been observed, but kinetic properties of the inhibition and the in vivo inhibition of the heavy metals on digestive enzymes are little understood. In the present study, in vitro inhibition of four metals (Pb, Cd, Zn and Hg) on the activity of {alpha}-amylase from the digestive gland of the green mussel will be compared. Their effects on the K{sub M} and V{sub max} values of {alpha}-amylase will also be compared. Finally, lead is either added to the food or water, to see how it affects the activity of {alpha}-amylase and how this effect acts in combination with starvation. 12 refs., 3 figs., 3 tabs.

  2. Improved activity and modulated action pattern obtained by random mutagenesis at the fourth beta-alpha loop involved in substrate binding to the catalytic (beta/alpha)8-barrel domain of barley alpha-amylase 1.

    PubMed

    Matsui, I; Svensson, B

    1997-09-01

    The functionality of the sequence Arg183-Gly184-Tyr185 of the substrate binding fourth beta-alpha loop in the (beta/alpha)8-barrel of barley alpha-amylase isozyme 1 (AMY1) was studied by random mutagenesis. A motif of polar Gly184 hydrophobic residues was present in active mutants, selected by starch plate screening of yeast transformants. Gly184 was important, probably due to the carbonyl group binding to Ca2+ and the spatial proximity of Phe181. Mutation of both flanking residues as in Ser183-Gly184-Met185 (SGM-) and TGL-AMY1 decreased the Ca2+ affinity. SGM-AMY1 has 2-fold increased activity for amylose but reduced activity on maltooligosaccharides, whereas KGY-AMY1 has up to 3-fold elevated activity toward the oligosaccharides. TGL-AMY1 has modest activity on all substrates. Shifted action pattern on maltooligosaccharides for NGY-, SGM-, and TGL-AMY1 support that Arg183 in wild type is located at subsites +1 and +2, accommodating two sugar rings toward the reducing end from the site of cleavage. In the crystal structure of barley alpha-amylase 2 (AMY2), Lys182 (equivalent to AMY1 Arg183) is hydrogen-bonded with sugar OH-3 in subsite +2. Higher Ki app for acarbose inhibition of KGY-AMY1 and parent AMY1 compared with the other mutants suggests favorable substrate interactions for Arg/Lys183. KGY-AMY1 was not inhibited by the AMY2-specific proteinaceous barley alpha-amylase/subtilisin inhibitor, although Lys182 of AMY2 is salt-linked to the inhibitor. PMID:9278396

  3. Structures of multi-branched dextrins produced by saccharifyiing alpha-amylase from starch.

    PubMed

    Umeki, K; Yamamoto, T

    1975-11-01

    From the digest of beta-limit dextrin (prepared from glutinous rice starch) with saccharifying alpha-amylase of Bacillus subtilis [EC 3.2.1.1] (BSA), two extensibely branched dextrins consisting of nine (No. 6, Fig. 1) and ten (No 7, Fig.1) glucose units were isolated by paper chromatography. Structural analysis using various enzymes revealed that No. 6 and No. 7 were both mixtures of four triply branched dextrins. They had structures which were built up with 63-alpha-glucosylmaltotriose and/or 62-alpha-glucosylmaltose as a linking unit. However, the branching configuration and the minimum alpha-1, 4-glucosidic linkages existing between two branches followed one of the three structures shown below: (see article). PMID:814118

  4. Production and characterization of thermostable alpha-amylase by thermophilic Geobacillus stearothermophilus.

    PubMed

    Al-Qodah, Zakaria

    2006-01-01

    Studies on the alpha-amylase-producing thermophilic bacterium isolated and identified from a hot spring in Jordan and designated as Geobacillus stearothermophilus JT2 were carried out. The optimum conditions for growth and enzyme production were pH 7 and 55 degrees C. The study of the kinetics of cellular growth indicated a mu(max) of 0.22/h, a K(s) of 1.2 g/L, a tau(d) of 3.15 h and a Y(x/s) of 0.43 g cell/g starch. In addition, the activation energy for growth and death were estimated and found to be 30.5 and 210 J/mol, respectively. The effect of different carbon and nitrogen sources on the cellular growth was tested. PMID:16927263

  5. A novel type of human alpha-amylase produced in lung carcinoid tumor.

    PubMed

    Tomita, N; Horii, A; Doi, S; Yokouchi, H; Shiosaki, K; Higashiyama, M; Matsuura, N; Ogawa, M; Mori, T; Matsubara, K

    1989-03-15

    A novel type of alpha-amylase was detected in a lung carcinoid tissue after surveying the cDNA library constructed from this tumor mRNA. Nucleotide sequence analysis showed that the amylase expressed in this carcinoid tumor has 13 and 6 amino acid substitutions when compared with salivary amylase (Amy1) and pancreatic amylase (Amy2), respectively. The nucleotide sequence homologies of cDNAs between this carcinoid amylase and amy1, amy2 are 97.5% and 98.2%, respectively. The nucleotide sequence comparison strongly suggests that this new amylase is the product of the amy3 gene that has been detected in human genome [Emi et al., Gene 62 (1988) 229-235] PMID:2701942

  6. Expression, purification and preliminary crystallographic studies of alpha-amylase isozyme 1 from barley seeds.

    PubMed

    Robert, Xavier; Gottschalk, Tine E; Haser, Richard; Svensson, Birte; Aghajari, Nushin

    2002-04-01

    The germinating barley seed contains two major alpha-amylase isozyme families, AMY1 and AMY2, involved in starch degradation to provide energy used by the plant embryo for growth. Many years of difficulty in growing three-dimensional crystals of natural AMY1 have now been overcome by a nonapeptide truncation of the enzyme C-terminus. The truncated enzyme was overexpressed in Pichia pastoris, purified and crystallized by the hanging-drop vapour-diffusion method using polyethylene glycol 8000 as precipitant and 2-propanol as an additive. Crystals belong to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 88.36, b = 72.82, c = 61.74 A and one molecule per asymmetric unit. PMID:11914496

  7. Effects of calcium ion concentration on starch hydrolysis of barley alpha-amylase isozymes.

    PubMed

    Yuk, Jeong-Bin; Choi, Seung-Ho; Lee, Tae-Hee; Jang, Myoung-Uoon; Park, Jung-Mi; Yi, Ah-Rum; Svensson, Birte; Kim, Tae-Jip

    2008-04-01

    Barley alpha-amylase genes, amy1 and amy2, were separately cloned into the expression vector of pPICZalphaA and recombinant Pichia strains were established by homologous recombination. Both AMYs from Pichia shared almost identical hydrolysis patterns on short maltooligosaccharides to result in glucose, maltose, or maltotriose. Against insoluble blue starch, AMY1 showed the highest activity at 0.1-5 mM calcium concentration, whereas 15-20 mM was optimal for AMY2. On the hydrolysis of soluble starch, unexpectedly, there was no significant difference between AMYs with increase of calcium. However, the relative activity on various starch substrates was significantly different between AMYs, which supports that the isozymes are clearly distinguished from each other on the basis of their unique preferences for substrates. PMID:18467868

  8. Three alpha-amylase genes of Aspergillus oryzae exhibit identical intron-exon organization.

    PubMed

    Wirsel, S; Lachmund, A; Wildhardt, G; Ruttkowski, E

    1989-01-01

    We have cloned three genes (amy1, amy2 and amy3) encoding alpha-amylase in the filamentous fungus Aspergillus oryzae. The established overall sequences have a very high degree of homology, showing divergences mainly in the 3'-untranslated regions. The positions and the sequences of the eight introns were found to be absolutely identical in the three genes. The sequence analysis of the 5'-regions revealed presumptive TATA, CAAT and GC boxes. Primer extension analysis was performed to determine the transcription start. We were able to detect mRNAs from amy1 and amy3 but not from amy2 with gene-specific oligonucleotide probes complementary to the 3'-noncoding regions. PMID:2785629

  9. Integration and expression of alpha-amylase and endoglucanase genes in the Lactobacillus plantarum chromosome.

    PubMed Central

    Scheirlinck, T; Mahillon, J; Joos, H; Dhaese, P; Michiels, F

    1989-01-01

    A commercial grass silage starter strain of Lactobacillus plantarum was transformed by high-frequency electroporation with plasmids containing an alpha-amylase gene from Bacillus stearothermophilus and an endoglucanase gene from Clostridium thermocellum. Both genes were expressed from their native regulatory signals, and active enzymes were found in the supernatant. However, the segregational stability of the transforming plasmids was rather low. Therefore, the transforming genes were inserted in the L. plantarum chromosome by means of single homologous recombination. In the majority of the transformants, this led to extremely stable segregation and expression of the transforming genes, without generating secondary mutations in the host. Increased selective pressure led to tandem amplification of the transforming DNA. The transformed strains demonstrated the ability of L. plantarum to express heterologous gene products; they can be used to detect the inoculum in silage ecology studies; and they demonstrate the feasibility of engineering truly cellulolytic silage starter bacteria. Images PMID:2679379

  10. Measurement of microbial alpha-amylases with p-nitrophenyl glycosides as the substrate complex.

    PubMed

    Trepeta, R W; Edberg, S C

    1984-01-01

    The detection of alpha-amylase is commonly used in clinical microbiology laboratories to aid in differentiating Streptococcus bovis from other streptococci. It is also useful in identifying Eikenella corrodens and the gravis subspecies of Corynebacterium diphtheriae and in separating species of the genera Bacteroides, Clostridium, Actinomyces, and Bacillus. Currently, the most frequently used procedure utilizes starch as the substrate and iodine as the indicator. Starch is incorporated into a agar medium, the isolate is inoculated on the surface, and the medium is incubated for 24 to 48 h. A 15-min test containing p-nitrophenyl polyglycosides as the substrate complex was developed to yield results comparable with the agar-based starch test. The reagent was made in liquid form, 0.20 ml per tube, and could be incubated either in ambient air or at 35 degrees C. When dried, the p-nitrophenyl polyglycoside reagent could be stored at 0 degrees C for 4 weeks. PMID:6418764

  11. Production, purification, and characterization of alpha-amylase from Thermomonospora curvata.

    PubMed Central

    Glymph, J L; Stutzenberger, F J

    1977-01-01

    Thermomonospora curvata produces an extracellular alpha-amylase. Maximal amylase production by cultures in a starch-mineral salts medium occurred at pH 7.5 and 53 degrees C. The crude enzyme was unstable to heating (65 degrees C) at pH 4 to 6, and was activated when heated at pH 8. The enzyme was purified 66-fold with a 9% yield and appeared homogeneous on discontinuous gel electrophoresis. The pH and temperature optima for activity of the purified enzyme were 5.5 to 6.0 and 65 degrees C. The molecular weight was calculated to be 62,000. The Km for starch was 0.39 mg/ml. The amylolytic pattern consisted of a mixture of maltotetraose and maltopentaose. Images PMID:21612

  12. Thermal stability of alpha-amylase from malted jowar (Sorghum bicolor).

    PubMed

    Kumar, R Siva Sai; Singh, Sridevi Annapurna; Rao, A G Appu

    2005-08-24

    Malted cereals are rich sources of alpha-amylase, which catalyzes the random hydrolysis of internal alpha-(1-4)-glycosidic bonds of starch, leading to liquefaction. Amylases play a role in the predigestion of starch, leading to a reduction in the water absorption capacity of the cereal. Among the three cereal amylases (barley, ragi, and jowar), jowar amylase is found to be the most thermostable. The major amylase from malted jowar, a 47 kDa alpha-amylase, purified to homogeneity, is rich in beta structure ( approximately 60%) like other cereal amylases. T(m), the midpoint of thermal inactivation, is found to be 69.6 +/- 0.3 degrees C. Thermal inactivation is found to follow first-order kinetics at pH 4.8, the pH optimum of the enzyme. Activation energy, E(a), is found to be 45.3 +/- 0.2 kcal mol(-)(1). The activation enthalpy (DeltaH), entropy (DeltaS*), and free energy change (DeltaG) are calculated to be 44.6 +/- 0.2 kcal mol(-)(1), 57.1 +/- 0.3 cal mol(-)(1) K(-)(1), and 25.2 +/- 0.2 kcal mol(-)(1), respectively. The thermal stability of the enzyme in the presence of the commonly used food additives NaCl and sucrose has been studied. T(m) is found to decrease to 66.3 +/- 0.3, 58.1 +/- 0.2, and 48.1 +/- 0.5 degrees C, corresponding to the presence of 0.1, 0.5, and 1 M NaCl, respectively. Sucrose acts as a stabilizer; the T(m) value is found to be 77.3 +/- 0.3 degrees C compared to 69.6 +/- 0.3 degrees C in the control. PMID:16104815

  13. [Alpha-amylase as an occupational allergen in baking industry employees].

    PubMed

    De Zotti, R; Larese, F; Molinari, S

    1994-01-01

    In a group of 226 bakers and pastry makers and in 88 students of a training school for bakers, we evaluated skin sensitization to the common allergens, wheat and alpha amylase. Skin prick tests were positive to the enzyme in 17 exposed subjects (7.5%) and in one student with previous occupational exposure as a baker; 27 exposed subjects (11.9%) and 2 students were sensitized to wheat. Among the 42 exposed workers who complained of work-related symptoms, 12 (28.6%) cases were skin positive to amylase and 17 (42.9%) to wheat. Among the 17 workers who were positive to amylase, 16 were also sensitized to wheat and/or common allergens, 12 complained of symptoms at work but since in many cases there was a positive response to wheat, too, it is impossible to speculate on the role of each allergen in inducing symptoms. One case, with work-related rhinoconjunctivitis, had skin sensitization only to alpha amylase but no specific IgE in the serum. These findings confirm that bakers are at risk of sensitization not only to wheat allergen but also to amylase from Aspergillus oryzae. The enzyme should be included in the list of substances to be tested among bakers in whom an occupational allergy is suspected, but particular care should be taken in evaluating the cutaneous response, especially if compared to wheat wheals. Further investigations are also needed to identify the source of risk and to better define the characteristics of the enzyme and the relationship between skin reaction to amylase, sensitization to wheat and atopy.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8072442

  14. Multiple time courses of salivary alpha-amylase and dimensions of affect in adolescence.

    PubMed

    Doane, Leah D; Van Lenten, Scott A

    2014-11-01

    Previous research has illustrated associations among daily experiences, emotions and stress-responding physiological systems. Recently, investigators have examined salivary alpha-amylase (sAA), a surrogate marker of the autonomic nervous system, and its associations with affect. The current study examined associations among affective valence, arousal and sAA across three different time courses at the momentary, daily and inter-individual level to understand varying influences of adolescents' daily emotional experiences on sAA reactivity and diurnal sAA activity. Adolescents (N=82) provided salivary samples and diary reports of affect and experiences five times a day for three consecutive days. They also completed self-report questionnaires on trait affect. Findings from multilevel growth curves demonstrated that adolescents in our sample displayed typical sAA diurnal rhythms with levels dropping 30 min after waking and then increasing across the day to a peak in the late afternoon. Within person momentary experiences of high arousal positive affect were associated with momentary sAA reactivity. Prior day experiences of high arousal negative affect were associated with a greater amylase awakening response (i.e., greater decrease) and flatter slopes the next day. Trait positive affect was also associated with flatter sAA slopes. Our findings suggest that both affective arousal and valence should be accounted for when examining differences in sAA reactivity and diurnal patterns. Further, our results indicated that emotion-physiology transactions among adolescents occur over varying time scales for salivary alpha-amylase as well as cortisol. PMID:25076484

  15. Isolation, characterization and inhibition by acarbose of the alpha-amylase from Lactobacillus fermentum: comparison with Lb. manihotivorans and Lb. plantarum amylases.

    PubMed

    Talamond, P; Desseaux, V; Moreau, Y; Santimone, M; Marchis-Mouren, G

    2002-11-01

    Extracellular alpha-amylase from Lactobacillus fermentum (FERMENTA) was purified by glycogen precipitation and ion exchange chromatography. The purification was approximately 28-fold with a 27% yield. The FERMENTA molecular mass (106,000 Da) is in the same range as the ones determined for L. amylovorus (AMYLOA), L. plantarum (PLANTAA) and L. manihotivorans (MANIHOA) alpha-amylases. The amino acid composition of FERMENTA differs from the other lactobacilli considered here, but however, indicates that the peptidic sequence contains two equal parts: the N-terminal catalytic part; and the C-terminal repeats. The isoelectric point of FERMENTA, PLANTAA, MANIHOA are approximately the same (3.6). The FERMENTA optimum pH (5.0) is slightly more acidic and the optimum temperature is lower (40 degrees C). Raw starch hydrolysis catalyzed by all three amylases liberates maltotriose and maltotretaose. Maltose is also produced by FERMENTA and MANIHOA. Maltohexaose FERMENTA catalyzed hydrolysis produces maltose and maltotriose. Finally, kinetics of FERMENTA, PLANTAA and MANIHOA using amylose as a substrate and acarbose as an inhibitor, were carried out. Statistical analysis of kinetic data, expressed using a general velocity equation and assuming rapid equilibrium, showed that: (1) in the absence of inhibitor k(cat)/Km are, respectively, 1x10(9), 12.6x10(9) and 3.2x10(9) s(-1) M(-1); and (2) the inhibition of FERMENTA is of the mixed non-competitive type (K(1i)=5.27 microM; L(1i)=1.73 microM) while the inhibition of PLANTAA and MANIHOA is of the uncompetitive type (L(1i)=1.93 microM and 1.52 microM, respectively). Whatever the inhibition type, acarbose is a strong inhibitor of these Lactobacillus amylases. These results indicate that, as found in porcine and barley amylases, Lactobacillus amylases contain in addition to the active site, a soluble carbohydrate (substrate or product) binding site. PMID:12431403

  16. Development of yeast strains for the efficient utilisation of starch: evaluation of constructs that express alpha-amylase and glucoamylase separately or as bifunctional fusion proteins.

    PubMed

    de Moraes, L M; Astolfi-Filho, S; Oliver, S G

    1995-11-01

    Eight constructions involving the Bacillus subtilis alpha-amylase gene (amyE), a mouse pancreatic alpha-amylase cDNA (AMY2) and an Aspergillus awamori glucoamylase cDNA (glaA) were prepared: three fusion genes, involving one alpha-amylase and the glucoamylase, two double-cassette plasmids (expressing one or other alpha-amylase and the glucoamylase) and three single-cassette plasmids, expressing the individual coding sequences. Following transformation of each plasmid into Saccharomyces cerevisiae, a plate test revealed that the largest starch hydrolysis halo was produced by the strain bearing the B. subtilis alpha-amylase/glucoamylase fusion (BsAAase/GAase), and the smallest halo by the one expressing the mouse pancreatic alpha-amylase/glucoamylase fusion (MAAase/GAase). When assayed for enzymatic activity in liquid medium, the strains bearing the fusion and the double-cassette plasmids involving B. subtilis alpha-amylase and the glucoamylase exhibited both enzymic activities. Moreover, the BsAAase/GAase hybrid was able to adsorb and digest raw starch. The MAAse/GAase fusion protein was found to exhibit only alpha-amylase activity. Finally, the capacity to grow on soluble and corn starch was tested in liquid medium for the strains bearing plasmids coding for the fusion proteins and the separate enzymes. The strain carrying the double-cassette BsAAase + GAase, which produced one of the smallest hydrolysis haloes in the place test, showed the best performance, not only in digesting soluble and corn starch but also in using all of the hydrolysis products for growth. The transformant bearing the BsAAase/GAase fusion was able to grow on soluble starch, but not on corn starch. PMID:8590658

  17. Aleurone nuclear proteins bind to similar elements in the promoter regions of two gibberellin-regulated alpha-amylase genes.

    PubMed

    Rushton, P J; Hooley, R; Lazarus, C M

    1992-09-01

    Binding of nuclear proteins from wild oat aleurone protoplasts to the promoter regions of two gibberellin-regulated wheat alpha-amylase genes (alpha-Amy1/18 and alpha-Amy2/54) has been studied by gel retardation and DNase 1 footprinting. Gel retardation studies using 300-430 bp fragments of the promoters showed similar binding characteristics with nuclear extracts from both gibberellin A1-treated and untreated protoplasts. DNase 1 footprints localised binding of nuclear proteins from gibberellin A1-treated aleurone protoplasts to regions in both promoters. Similar sequence elements in the promoter regions of both genes were protected from digestion although the location and number of footprints in each promoter region were different. Each footprint contained either a sequence similar to the cAMP and/or phorbol ester response elements, or a hyphenated palindrome sequence. The presence of cAMP and/or phorbol ester response element-like sequences in the footprints suggests that transcription factors of the bZIP type may be involved in the expression of alpha-amylase genes in aleurone cells. Footprints containing hyphenated palindrome sequences, found in the promoter regions of both genes, suggest the possible involvement of other classes of transcription factor. The conserved alpha-amylase promoter sequence TAA-CAGA was also shown to bind nuclear protein in the alpha-Amy2/54 promoter. These observations are discussed in relation to alpha-amylase gene expression in aleurone and to functional data concerning these genes. PMID:1511135

  18. Cloning and expression of Lipomyces starkeyi alpha-amylase in Escherichia coli and determination of some of its properties.

    PubMed

    Kang, Hee Kyoung; Lee, Jin Ha; Kim, Doman; Day, Donal F; Robyt, John F; Park, Kwan-Hwa; Moon, Tae-Wha

    2004-04-01

    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). PMID:15043869

  19. A novel raw starch digesting alpha-amylase from a newly isolated Bacillus sp. YX-1: purification and characterization.

    PubMed

    Liu, Xu Dong; Xu, Yan

    2008-07-01

    This study reports the purification and characterization of a novel raw starch digesting alpha-amylase from a newly isolated Bacillus sp. YX-1. Maximum alpha-amylase activity (53 U mL(-1)) was obtained at 45 degrees C after 44 h of incubation. The enzyme was purified using ammonium sulfate precipitation, ion exchange and gel filtration chromatography, and showed a molecular weight of 56 kDa by SDS-PAGE. This enzyme exhibited maximum activity at pH 5.0, performed stability over a broad range of pH 4.5-11.0, and was optimally active at 40-50 degrees C. The enzyme preparation had a strong digesting ability towards various raw starches and efficiently hydrolyzed raw corn starch at a concentration of 20% and pH 5.0, which were normally used in the starch industries, in a period of 12h. By analyzing its partial amino acid sequences, the enzyme was proposed to be a novel alpha-amylase. PMID:17920264

  20. Diurnal patterns of salivary alpha-amylase and cortisol secretion in female adolescent tennis players after 16 weeks of training.

    PubMed

    Filaire, Edith; Ferreira, Jose Pedro; Oliveira, Miguel; Massart, Alain

    2013-07-01

    We examined the effects of 16 weeks of training on diurnal pattern of salivary alpha-amylase (sAA), cortisol, and the ratio of sAA over cortisol (AOC) in 12 national adolescent female tennis players. Stress and recovery were also evaluated using the Recovery-Stress-Questionnaire for Athletes-RESTQ-Sport. Data were collected after a 2-week rest (January, W0), and 4 months after W0 (W16). Subjects collected five saliva samples throughout a day. While all participants displayed the previously shown decrease after awakening in adolescents at W0, they showed a rise in the alpha-amylase awakening response and a higher alpha-amylase activity output (p<0.01) at W16 compared to W0. For the daily rhythm of cortisol we found subjects having a low overall output of salivary cortisol (p<0.01) and a blunted response to awakening at W16. Furthermore, an increase in the ratio AOC at W16, and a negative correlation between this ratio and Sport-specific recovery score. Our findings offer support for the hypothesis that increase of training load during the study period induced asymmetry activation between the two stress systems, in relation to psychological alterations and performance decrease. These results provide encouragement to continue exploring the impact of training program using a psychobiological approach among young athletes in order to prevent fatigue and preserve the health of these athletes. PMID:23200107

  1. A single residue mutation abolishes attachment of the CBM26 starch-binding domain from Lactobacillus amylovorus alpha-amylase.

    PubMed

    Rodríguez-Sanoja, Romina; Oviedo, N; Escalante, L; Ruiz, B; Sánchez, S

    2009-03-01

    Starch is degraded by amylases that frequently have a modular structure composed of a catalytic domain and at least one non-catalytic domain that is involved in polysaccharide binding. The C-terminal domain from the Lactobacillus amylovorus alpha-amylase has an unusual architecture composed of five tandem starch-binding domains (SBDs). These domains belong to family 26 in the carbohydrate-binding modules (CBM) classification. It has been reported that members of this family have only one site for starch binding, where aromatic amino acids perform the binding function. In SBDs, fold similarities are better conserved than sequences; nevertheless, it is possible to identify in CBM26 members at least two aromatic residues highly conserved. We attempt to explain polysaccharide recognition for the L. amylovorus alpha-amylase SBD through site-directed mutagenesis of aromatic amino acids. Three amino acids were identified as essential for binding, two tyrosines and one tryptophan. Y18L and Y20L mutations were found to decrease the SBD binding capacity, but unexpectedly, the mutation at W32L led to a total loss of affinity, either with linear or ramified substrates. The critical role of Trp 32 in substrate binding confirms the presence of just one binding site in each alpha-amylase SBD. PMID:19052787

  2. Solution of the structure of Aspergillus niger acid alpha-amylase by combined molecular replacement and multiple isomorphous replacement methods.

    PubMed

    Brady, R L; Brzozowski, A M; Derewenda, Z S; Dodson, E J; Dodson, G G

    1991-08-01

    The crystal structure of Aspergillus niger acid alpha-amylase was solved by a combination of multiple isomorphous replacement and molecular replacement methods. The atomic coordinates of Aspergillus oryzae (TAKA) alpha-amylase (entry 2TAA in the Protein Data Bank) and experimental diffraction data from a new monoclinic crystal form of TAKA alpha-amylase, were used during the procedure. Sequence identity between the two proteins is approximately 80%. The atomic parameters derived from the molecular replacement solution were too inaccurate to initiate least-squares crystallographic refinement. The molecular model was extensively revised against the experimental electron density map calculated at 3 A resolution. Subsequent crystallographic refinement of this model using synchrotron data to 2.1 A resolution led to a conventional R factor of 16.8%. The structure conforms well to expected stereochemistry with bond lengths deviating from target values by 0.031 A, and planar groups showing a root-mean-square deviation from ideal planes of 0.025 A. PMID:1930834

  3. Harsh discipline and behavior problems: the moderating effects of cortisol and alpha-amylase.

    PubMed

    Chen, Frances R; Raine, Adrian; Rudo-Hutt, Anna S; Glenn, Andrea L; Soyfer, Liana; Granger, Douglas A

    2015-01-01

    Numerous studies link harsh discipline to adjustment problems in youth, yet not all individuals exposed to harsh discipline develop behavior problems. Contemporary theory suggests that this relationship could be moderated by individual differences in environmentally sensitive biological systems. This study investigated whether the interaction between hypothalamic-pituitary-adrenal (HPA) activity and autonomic nervous system (ANS) arousal moderated the link between harsh discipline and behavior problems. Three saliva samples were collected on a single day from 425 inner city youth (50% male, age 11-12 years, 80% African American) and were later assayed for cortisol (HPA) and alpha-amylase (ANS). Problem behavior was assessed by self- and parent-report using the Child Behavior Checklist. Youth also reported the level of harsh discipline that they experienced. Harsh discipline was positively associated with externalizing and internalizing problems only when there were asymmetrical profiles of HPA activity and ANS arousal. This pattern was evident for boys but not girls. Findings are discussed in relation to prevailing theories suggesting that biological susceptibility translates adversity into risk for behavior problems. PMID:25451383

  4. Aspergillus oryzae S2 alpha-amylase production under solid state fermentation: optimization of culture conditions.

    PubMed

    Sahnoun, Mouna; Kriaa, Mouna; Elgharbi, Fatma; Ayadi, Dorra-Zouari; Bejar, Samir; Kammoun, Radhouane

    2015-04-01

    Aspergillus oryzae S2 was assayed for alpha-amylase production under solid state fermentation (SSF). In addition to AmyA and AmyB already produced in monitored submerged culture, the strain was noted to produce new AmyB oligomeric forms, in particular a dominant tetrameric form named AmyC. The latter was purified to homogeneity through fractional acetone precipitation and size exclusion chromatography. SDS-PAGE and native PAGE analyses revealed that, purified AmyC was an approximately 172 kDa tetramer of four 42 kDa subunits. AmyC was also noted to display the same NH2-terminal amino acid sequence residues and approximately the same physico-chemical properties of AmyA and AmyB, to exhibit maximum activity at pH 5.6 and 60 °C, and to produce maltose and maltotriose as major starch hydrolysis end-products. Soyabean meal was the best substitute to yeast extract compared to fish powder waste and wheat gluten waste. AmyC production was optimized under SSF using statistical design methodology. Moisture content of 76.25%, C/N substrate ratio of 0.62, and inoculum size of 10(6.87) spores allowed maximum activity of 22118.34 U/g of dried substrate, which was 33 times higher than the one obtained before the application of the central composite design (CCD). PMID:25617840

  5. Effects of simulated firefighting on the responses of salivary cortisol, alpha-amylase and psychological variables.

    PubMed

    Perroni, F; Tessitore, A; Cibelli, G; Lupo, C; D'Artibale, E; Cortis, C; Cignitti, L; De Rosas, M; Capranica, L

    2009-04-01

    The aim of this study was to evaluate the effects of a simulated firefighting intervention on salivary alpha-amylase (sA-A), free cortisol (sC), anxiety (STAI), and profile of mood states (POMS) in 20 male firefighters (age 32 +/- 1 years, VO(2peak): 43 +/- 5 ml/kg per min). During the 12-min firefighting intervention (ambient temperature: 13 +/- 1 degrees C; relative humidity: 63 +/- 1%), individuals spent 63 +/- 28% of the time working at heart rate (HR) >85% of individual HR(max), [La] (peak) 9.2 +/- 2.9 mM and ratings of perceived exertion 16 +/- 2. At 30 min post-intervention significant (p < 0.001) increases in sA-A (174%) and sC (109%) were found with regard to values recorded before and after 90 min of the firefighting intervention. Since no differences emerged between pre-intervention and post intervention for STAI and POMS values, the hormonal changes were attributable to the intense physical stress of the simulated intervention. Further research is needed during real firefighting activities, where high emotional stress may also be present. PMID:19401900

  6. Salivary nitric oxide and alpha-amylase as indexes of training intensity and load.

    PubMed

    Diaz, M M; Bocanegra, O L; Teixeira, R R; Soares, S S; Espindola, F S

    2013-01-01

    This study examined the variation in salivary nitric oxide (NO), alpha-amylase (sAA) and serum markers of muscle injury during 21 weeks of training in elite swimmers. Samples of saliva and blood were collected once a month during 5 months from 11 male professional athletes during their regular training season. The variation in each marker throughout the 21 weeks was compared with the dynamics of training volume, intensity and load. Unstimulated whole saliva was assessed for NO and sAA whereas venous blood was assessed for lactate dehydrogenase, creatine kinase, and γ-glutamyltransferase. Nitric oxide and sAA showed a proportional response to the intensity of training. However, whereas the concentration of NO increased across the 21 weeks, the activity of sAA decreased. Similar variations in the concentration of NO and the markers of muscle injury were also observed. The higher concentration of NO might be attributed to changes in haemodynamics and muscle regenerative processes. On the other hand, autonomic regulation towards parasympathetic predominance might have been responsible for the decrease in sAA activity. These findings provide appealing evidence for the utilization of salivary constituents in sports medicine to monitor training programmes. PMID:22960992

  7. Effects of alpha-amylase on in vitro growth of Legionella pneumophila.

    PubMed Central

    Bortner, C A; Miller, R D; Arnold, R R

    1983-01-01

    Sterile parotid saliva inhibited growth of Legionella pneumophila on solid media, and the salivary component involved in this inhibition has been shown to be amylase. Disk diffusion and well plate assays were used to study possible mechanisms for this effect. The amylolytic activity of saliva copurified with inhibitory activity, and both activities were sensitive to proteinase K digestion and heat treatment. In addition, purified alpha-amylase from several sources (bacteria, fungi, porcine pancreas, and human saliva) exhibited similar activity. Incorporation of charcoal or bovine serum albumin into media blocked inhibition by amylase. Replacement of Bacto-Agar with Noble agar (both from Difco Laboratories) prevented growth inhibition in the absence of starch. However, when corn starch was present with Noble agar, amylase-induced growth inhibition occurred. Purification of starch by washing with methanol eliminated some toxic component. The toxic component from starch could be recovered from the methanol wash and inhibited growth of L. pneumophila in the absence of amylase activity. The results suggest that toxic substances exist in media components which may be unmasked during salivary amylase digestion of starch. This effect may explain, in part, the difficulty in recovery of the organism from clinical specimens containing amylase. PMID:6190756

  8. Cloning and Characterization of an alpha-amylase Gene from the Hyperthermophilic Archaeon Thermococcus Thioreducens

    NASA Technical Reports Server (NTRS)

    Bernhardsdotter, Eva C. M. J.; Pusey, Mark L.; Ng, Joseph D.; Garriott, Owen K.

    2004-01-01

    The gene encoding an extracellular alpha-amylase, TTA, from the hyperthermophilic archaeon Thermococcus thioreducens was cloned and expressed in Escherichia coli. Primary structural analysis revealed high similarity with other a-amylases from the Thermococcus and Pyrococcus genera, as well as the four highly conserved regions typical for a-amylases. The 1374 bp gene encodes a protein of 457 amino acids, of which 435 constitute the mature protein preceded by a 22 amino acid signal peptide. The molecular weight of the purified recombinant enzyme was estimated to be 43 kDa by denaturing gel electrophoresis. Maximal enzymatic activity of recombinant TTA was observed at 90 C and pH 5.5 in the absence of exogenous Ca(2+), and the enzyme was considerably stable even after incubation at 90 C for 2 hours. The thermostability at 90 and 102 C was enhanced in the presence of 5 mM Ca(2+). The extraordinarily high specific activity (about 7.4 x 10(exp 3) U/mg protein at 90 C, pH 5.5 with soluble starch as substrate) together with its low pH optimum makes this enzyme an interesting candidate for starch processing applications.

  9. Variation in salivary and pancreatic alpha-amylase genes in Italian horse breeds.

    PubMed

    Coizet, Beatrice; Nicoloso, Letizia; Marletta, Donata; Tamiozzo-Calligarich, Alessandra; Pagnacco, Giulio; Crepaldi, Paola

    2014-01-01

    The dietary demand of the modern horse relies on high-cereal feeding and limited forage compared with natural grazing conditions, predisposing the horse to several important diseases. Salivary and pancreatic alpha-amylases (coded by AMY1 and AMY2 genes, respectively) play a crucial role in carbohydrate digestion in nonruminants, but little is known about these 2 genes in the horse. Aim of this work has been to distinguish genomic sequences of horse AMY1 and AMY2 genes and to analyze any polymorphisms in breeds historically characterized by marked differences in nutritional management. A single nucleotide polymorphism detection was performed and 7 novel single nucleotide polymorphisms were found. Three single nucleotide polymorphisms are in exons and were genotyped in 112 horses belonging to 6 breeds. One single nucleotide polymorphism in AMY1 gene distinguished Haflinger and the Italian native Murgese from the other breeds, whereas both the single nucleotide polymorphisms in AMY2 gene showed different allelic frequencies in Friesian compared with the other breeds. These differences are confirmed by quite high fixation index (Fst) values for these 2 nonsynonymous single nucleotide polymorphisms. These preliminary results highlight marked divergences in allele frequencies of AMY1 and AMY2 genes, involved in starch digestion, between horse breeds characterized by different histories of selection, thus providing first indications of possible relations between genetics and nutritional management. PMID:24558100

  10. Cortisol and alpha amylase reactivity and timing of puberty: Vulnerabilities for antisocial behaviour in young adolescents

    PubMed Central

    Susman, Elizabeth J.; Granger, Douglas A; Blades, Keeva T.; Randazzo, William; Heaton, Jodi A.; Dorn, Lorah D.

    2009-01-01

    The theoretical framework proposed that cortisol and saliva alpha amylase (sAA) reactivitiy are vulnerabilities for antisocial behaviour. These indices of hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenal-medulary (SAM) components of the stress system, respectively, were considered vulnerabilities that also interact with the putative stressful transition of timing of puberty to predispose adolescents toward antisocial behaviour. The sample consisted of 8- to-13-year-old boys and girls (N=135) and a parent. For boys, timing of puberty moderated the association between cortisol and sAA reactivity and antisocial behaviour. Higher cortisol reactivity in later timing boys was related to a composite index of antisocial behaviour and rule-breaking behaviour problems. In contrast, lower sAA reactivity and earlier timing of puberty in boys was related to rule breaking and conduct disorder symptoms. The interaction between timing of puberty and HPA or SAM regulation and timing of puberty in boys suggests that reproductive, neuroendocrine mechanisms may be involved in the extensively documented adverse consequences of off-time pubertal development. PMID:19819639

  11. Alpha-amylase inhibitory activity and sterol composition of the marine algae, Sargassum glaucescens

    PubMed Central

    Payghami, Nasrin; Jamili, Shahla; Rustaiyan, Abdolhossein; Saeidnia, Soodabeh; Nikan, Marjan; Gohari, Ahmad Reza

    2015-01-01

    Background: Sargassum species (phaeophyceae) are economically important brown algae in southern parts of Iran. Sargassum is mainly harvested as a row material in alginate production industries and is a source of plant foods or plant bio-stimulants even a component of animal foods. Objective: In this study, Sargassum glaucescens, collected from the seashore of Chabahar, was employed for phytochemical and biological evaluations. Materials and Methods: For that purpose, the dried algae was extracted by methanol and subjected to different chromatographic separation methods. Results: Six sterols, fucosterol (1), 24(S)-hydroxy-24-vinylcholesterol (2), 24(R)-hydroxy-24-vinylcholesterol (3), stigmasterol (4), β-sitosterol (5) and cholesterol (6) were identified by spectroscopic methods including 1H-NMR, 13C-NMR and mass spectroscopy. In vitro alpha-amylase inhibitory test was performed on the methanolic extract and the results revealed a potent inhibition (IC50 = 8.9 ± 2.4 mg/mL) of the enzyme compared to acarbose as a positive control. Conclusion: Various biological activities and distribution of sterols in Sargassum genus have been critically reviewed here. The results concluded that these algae are a good candidate for further anti-diabetic investigations in animals and human. PMID:26692744

  12. Production and characterization of alpha-amylase from Aspergillus niger JGI 24 isolated in Bangalore.

    PubMed

    Varalakshmi, K N; Kumudini, B S; Nandini, B N; Solomon, J; Suhas, R; Mahesh, B; Kavitha, A P

    2009-01-01

    Five fungal isolates were screened for the production of alpha-amylase using both solid-state and submerged fermentations. The best amylase producer among them, Aspergillus niger JGI 24, was selected for enzyme production by solid-state fermentation (SSF) on wheat bran. Different carbon and nitrogen supplements were used to enhance enzyme production and maximum amount of enzyme was obtained when SSF was carried out with soluble starch and beef extract (1% each) as supplements. Further attempts to enhance enzyme production by UV induced mutagenesis were carried out. Survival rate decreased with increase in duration of UV exposure. Partial purification of the enzyme using ammonium sulphate fractionation resulted in 1.49 fold increase in the enzyme activity. The enzyme showed a molecular weight of 43 kDa by SDS-PAGE. Metal ions Ca2+ and Co2+ increased the enzyme activity. The enzyme was optimally active at 30 degrees C and pH 9.5. PMID:19469283

  13. Job categories and their effect on exposure to fungal alpha-amylase and inhalable dust in the U.K. baking industry.

    PubMed

    Elms, Joanne; Beckett, Paul; Griffin, Peter; Evans, Paul; Sams, Craig; Roff, Martin; Curran, Andrew D

    2003-01-01

    Enzymes in flour improver, in particular fungal alpha-amylase, are known to be a significant cause of respiratory allergy in the baking industry. This study measured total inhalable dust and fungal alpha-amylase exposures in U.K. bakeries, mills, and a flour improver production and packing facility and determined whether assignment of job description could identify individuals with the highest exposures to fungal alpha-amylase and inhalable dust. A total of 117 personal samples were taken for workers in 19 bakeries, 2 mills, and a flour improver production and packing facility and were analyzed using a monoclonal based immunoassay. Occupational hygiene surveys were undertaken for each site to assign job description and identify individuals who worked directly with flour improvers. Analysis of exposure data identified that mixers and weighers from large bakeries had the highest exposures to both inhalable dust and fungal alpha-amylase among the different categories of bakery workers (p<.01). Currently, the maximum exposure limit for flour dust in the United Kingdom is 10 mg/m(3) (8-hour time-weighted average reference period). In this study 25% of the total dust results for bakers exceeded 10 mg/m(3), and interestingly, 63% of the individuals with exposure levels exceeding 10 mg/m(3) were weighers and mixers. Individuals who worked directly with flour improvers were exposed to higher levels of both inhalable dust and fungal alpha-amylase (p<.01) than those who were not directly handling these products. Before sensitive immunoassays were utilized for the detection of specific inhalable allergens, gravimetric analysis was often used as a surrogate. There was a weak relationship between inhalable dust and fungal alpha-amylase exposures; however, inhalable dust levels could not be used to predict amylase exposures, which highlights the importance of measuring both inhalable dust and fungal alpha-amylase exposures. PMID:12908861

  14. LaaA, a novel high-active alkalophilic alpha-amylase from deep-sea bacterium Luteimonas abyssi XH031(T).

    PubMed

    Song, Qinghao; Wang, Yan; Yin, Chong; Zhang, Xiao-Hua

    2016-08-01

    Alpha-amylase is a kind of broadly used industrial enzymes, most of which have been exploited from terrestrial organism. Comparatively, alpha-amylase from marine environment was largely undeveloped. In this study, a novel alkalophilic alpha-amylase with high activity, Luteimonas abyssi alpha-amylase (LaaA), was cloned from deep-sea bacterium L. abyssi XH031(T) and expressed in Escherichia coli BL21. The gene has a length of 1428bp and encodes 475 amino acids with a 35-residue signal peptide. The specific activity of LaaA reached 8881U/mg at the optimum pH 9.0, which is obvious higher than other reported alpha-amylase. This enzyme can remain active at pH levels ranging from 6.0 to 11.0 and temperatures below 45°C, retaining high activity even at low temperatures (almost 38% residual activity at 10°C). In addition, 1mM Na(+), K(+), and Mn(2+) enhanced the activity of LaaA. To investigate the function of potential active sites, R227G, D229K, E256Q/H, H327V and D328V mutants were generated, and the results suggested that Arg227, Asp229, Glu256 and Asp328 were total conserved and essential for the activity of alpha-amylase LaaA. This study shows that the alpha-amylase LaaA is an alkali-tolerant and high-active amylase with strong potential for use in detergent industry. PMID:27241296

  15. Psychosocial determinants of diurnal alpha-amylase among healthy Quebec workers.

    PubMed

    Marchand, Alain; Juster, Robert-Paul; Lupien, Sonia J; Durand, Pierre

    2016-04-01

    Salivary alpha-amylase (sAA) is a stress-sensitive biomarker the shows promise as an indirect proxy of sympathetic-adrenal-medullary axis activities that are otherwise difficult to discern non-invasively. This comprehensive study investigated diurnal sAA in association with numerous psychosocial characteristics related to mental health, work stress, and non-work stress. Participants included 395 workers (56.1% women, age: M=41.3, SD=10.81) from across 34 distinct workplaces. Diurnal sAA was sampled over two non-consecutive work days at awakening, 30min after awakening, 14h00, 16h00, and bedtime. Well-validated psychometrics and survey items were used to measure mental health (psychological distress, depression, burnout, work characteristics) (task design, demands, social relations, gratifications), and non-work characteristics (marital/parental status, economic statuses, marital and parental stress, work-family conflicts). Preliminary results revealed that men showed occasionally higher sAA concentrations than women. Multilevel regressions were used to analyze sAA concentrations nested according to levels (i) for each time-point, (ii) between workers, and (iii) across workplaces while covarying for time of awakening, sex, age, cigarette smoking, alcohol consumption, regular physical activity, psychotropic drug use, and body mass index. Main results revealed that psychological demands, support from colleagues, interpersonal conflicts, job recognition and job insecurity appear to be associated with diurnal sAA, while non-work factors did not. Our findings showing a distinct diurnal profile for sAA replicate and expand those of Nater et al. (2007, Psychoneuroendocrinology 32, 392-401), providing further evidence that sAA is associated to subjective psychosocial factors. PMID:26799849

  16. Salivary alpha amylase and salivary cortisol response to fluid consumption in exercising athletes.

    PubMed

    Backes, T P; Horvath, P J; Kazial, K A

    2015-11-01

    The objective of the study was to examine salivary biomarker response to fluid consumption in exercising athletes. Exercise induces stress on the body and salivary alpha amylase (sAA) and salivary cortisol are useful biomarkers for activity in the sympathoadrenal medullary system and the hypothalamic pituitary adrenal axis which are involved in the stress response. Fifteen college students were given 150 ml and 500 ml of water on different days and blinded to fluid condition. The exercise protocol was identical for both fluid conditions using absolute exercise intensities ranging from moderate to high. Saliva was collected prior to exercise, post moderate and post high intensities and analyzed by Salimetrics assays. Exercise was significant for sAA with values different between pre-exercise (85 ± 10 U · ml(-1)) and high intensity (284 ± 30 U · ml(-1)) as well as between moderate intensity (204 ± 32 U · ml(-1)) and high intensity. There was no difference in sAA values between fluid conditions at either intensity. Exercise intensity and fluid condition were each significant for cortisol. Cortisol values were different between pre-exercise (0.30 ± 0.03 ug · dL(-1)) and high intensity (0.45 ± 0.05 ug · dL(-1)) as well as between moderate intensity (0.33 ± 0.04 ug · dL(-1)) and high intensity. Moderate exercise intensity cortisol was lower in the 500 ml condition (0.33 ± 0.03 ug · dL(-1)) compared with the 150 ml condition (0.38 ± 0.03 ug · dL(-1)). This altered physiological response due to fluid consumption could influence sport performance and should be considered. In addition, future sport and exercise studies should control for fluid consumption. PMID:26681828

  17. Cell-associated alpha-amylases of butyrate-producing Firmicute bacteria from the human colon.

    PubMed

    Ramsay, Alan G; Scott, Karen P; Martin, Jenny C; Rincon, Marco T; Flint, Harry J

    2006-11-01

    Selected butyrate-producing bacteria from the human colon that are related to Roseburia spp. and Butyrivibrio fibrisolvens showed a good ability to utilize a variety of starches for growth when compared with the Gram-negative amylolytic anaerobe Bacteroides thetaiotaomicron. A major cell-associated amylase of high molecular mass (140-210 kDa) was detected in each strain by SDS-PAGE zymogram analysis, and genes corresponding to these enzymes were analysed for two representative strains. Amy13B from But. fibrisolvens 16/4 is a multi-domain enzyme of 144.6 kDa that includes a family 13 glycoside hydrolase domain, and duplicated family 26 carbohydrate-binding modules. Amy13A (182.4 kDa), from Roseburia inulinivorans A2-194, also includes a family 13 domain, which is preceded by two repeat units of approximately 116 aa rich in aromatic residues, an isoamylase N-terminal domain, a pullulanase-associated domain, and an additional unidentified domain. Both Amy13A and Amy13B have N-terminal signal peptides and C-terminal cell-wall sorting signals, including a modified LPXTG motif similar to that involved in interactions with the cell surface in other Gram-positive bacteria, a hydrophobic transmembrane segment, and a basic C terminus. The overexpressed family 13 domains showed an absolute requirement for Mg2+ or Ca2+ for activity, and functioned as 1,4-alpha-glucanohydrolases (alpha-amylases; EC 3.2.1.1). These major starch-degrading enzymes thus appear to be anchored to the cell wall in this important group of human gut bacteria. PMID:17074899

  18. Alpha-amylase reactivity in relation to psychopathic traits in adults.

    PubMed

    Glenn, Andrea L; Remmel, Rheanna J; Raine, Adrian; Schug, Robert A; Gao, Yu; Granger, Douglas A

    2015-04-01

    Recent investigations of the psychobiology of stress in antisocial youth have benefited from a multi-system measurement model. The inclusion of salivary alpha-amylase (sAA), a surrogate marker of autonomic/sympathetic nervous system (ANS) activity, in addition to salivary cortisol, a biomarker of the hypothalamic-pituitary-adrenal (HPA) axis functioning, has helped define a more complete picture of individual differences and potential dysfunction in the stress response system of these individuals. To the authors' knowledge, no studies have examined sAA in relation to antisocial behavior in adults or in relation to psychopathic traits specifically. In the present study, we examined sAA, in addition to salivary cortisol, in a relatively large sample (n=158) of adult males (M age=36.81, range=22-67 years; 44% African-American, 34% Caucasian, 16% Hispanic) recruited from temporary employment agencies with varying levels of psychopathic traits. Males scoring highest in psychopathy were found to have attenuated sAA reactivity to social stress compared to those scoring lower in psychopathy. No differential relationships with the different factors of psychopathy were observed. In contrast to studies of antisocial youth, there were no interactions between sAA and cortisol levels in relation to psychopathy, but there was a significant interaction between pre-stressor levels of sAA and cortisol. Findings reveal potential regulatory deficits in the fast-acting, 'fight or flight', component of the stress response in adult males with psychopathic traits, as well as abnormalities in how this system may interact with the HPA axis. PMID:25662339

  19. Elevated Salivary Alpha Amylase in Adolescent Sexual Abuse Survivors with Posttraumatic Stress Disorder Symptoms

    PubMed Central

    Strawn, Jeffrey R.; Out, Dorothee; Granger, Douglas A.; Putnam, Frank W.

    2015-01-01

    Abstract Objective: Little is known regarding neuroendocrine responses in adolescent girls with posttraumatic stress disorder (PTSD) who have experienced sexual abuse. Therefore, we collected saliva samples three times daily for 3 days to assess concentrations of salivary alpha amylase (sAA) – a surrogate marker for autonomic nervous system (ANS) activity and, in particular, sympathetic activity – in sexually abused adolescent girls. Methods: Twenty-four girls (mean age: 15±1.4 years) who had experienced recent sexual abuse (i.e., sexual abuse occurred 1–6 months prior to study enrollment) and 12 healthy comparison subjects (mean age: 14.8±1.3 years) completed a structured interview and assessments to ascertain symptoms of posttraumatic stress, then collected saliva at home upon awakening, 30 minutes after waking, and at 5 p.m. on three consecutive school days. Results: For sexually abused girls, total PTSD symptoms were associated with higher overall morning levels of sAA (r[20]=0.51, p=0.02), a finding driven by intrusive symptoms (r[20]=0.43, p<0.05) and hyperarousal symptoms (r[20]=0.58, p=0.01). There were no significant differences in diurnal sAA secretion between the sexually abused girls and healthy comparison adolescents. Conclusions: Overall morning concentrations of sAA in sexually abused girls are associated with overall PTSD severity as well as symptoms of hyperarousal and intrusive symptoms, possibly reflecting symptom-linked increases in ANS tone. These data raise the possibility that alterations in ANS activity are related to the pathophysiology of sexual abuse-related PTSD in adolescent girls, and may inform therapeutic interventions (e.g., antiadrenergic medications). PMID:25803321

  20. Diacylglycerol pyrophosphate inhibits the alpha-amylase secretion stimulated by gibberellic acid in barley aleurone.

    PubMed

    Racagni, Graciela; Villasuso, Ana L; Pasquaré, Susana J; Giusto, Norma M; Machado, Estela

    2008-11-01

    ABA plays an important regulatory role in seed germination because it inhibits the response to GA in aleurone, a secretory tissue surrounding the endosperm. Phosphatidic acid (PA) is a well-known intermediary in ABA signaling, but the role of diacylglycerol pyrophosphate (DGPP) in germination processes is not clearly established. In this study, we show that PA produced by phospholipase D (E.C. 3.1.4.4) during the antagonist effect of ABA in GA signaling is rapidly phosphorylated by phosphatidate kinase (PAK) to DGPP. This is a crucial fact for aleurone function because exogenously added dioleoyl-DGPP inhibits secretion of alpha-amylase (E.C. 3.2.1.1). Aleurone treatment with ABA and 1-butanol results in normal secretory activity, and this effect is reversed by addition of dioleoyl-DGPP. We also found that ABA decreased the activity of an Mg2+-independent, N-ethylmaleimide-insensitive form of phosphatidate phosphohydrolase (PAP2) (E.C. 3.1.3.4), leading to reduction of PA dephosphorylation and increased PAK activity. Sequence analysis using Arabidopsis thaliana lipid phosphate phosphatase (LPP) sequences as queries identified two putative molecular homologues, termed HvLPP1 and HvLPP2, encoding putative Lpps with the presence of well-conserved structural Lpp domains. Our results are consistent with a role of DGPP as a regulator of ABA antagonist effect in GA signaling and provide evidence about regulation of PA level by a PAP2 during ABA response in aleurone. PMID:18573189

  1. Alpha-Amylase Reactivity in Relation to Psychopathic Traits in Adults

    PubMed Central

    Glenn, Andrea L.; Remmel, Rheanna J.; Raine, Adrian; Schug, Robert A.; Gao, Yu; Granger, Douglas A.

    2015-01-01

    Recent investigations of the psychobiology of stress in antisocial youth have benefited from a multi-system measurement model. The inclusion of salivary alpha-amylase (sAA), a surrogate marker of autonomic/sympathetic nervous system (ANS) activity, in addition to salivary cortisol, a biomarker of the hypothalamic-pituitary-adrenal (HPA) axis functioning, has helped define a more complete picture of individual differences and potential dysfunction in the stress response system of these individuals. To the authors' knowledge, no studies have examined sAA in relation to antisocial behavior in adults or in relation to psychopathic traits specifically. In the present study, we examined sAA, in addition to salivary cortisol, in a relatively large sample (n = 158) of adult males (M age = 36.81, range = 22-67 years; 44% African-American, 34% Caucasian, 16% Hispanic) recruited from temporary employment agencies with varying levels of psychopathic traits. Males scoring highest in psychopathy were found to have attenuated sAA reactivity to social stress compared to those scoring lower in psychopathy. No differential relationships with the different factors of psychopathy were observed. In contrast to studies of antisocial youth, there were no interactions between sAA and cortisol levels in relation to psychopathy, but there was a significant interaction between pre-stressor levels of sAA and cortisol. Findings reveal potential regulatory deficits in the fast-acting, ‘fight or flight’, component of the stress response in adult males with psychopathic traits, as well as abnormalities in how this system may interact with the HPA axis. PMID:25662339

  2. Salivary alpha amylase and salivary cortisol response to fluid consumption in exercising athletes

    PubMed Central

    Horvath, PJ; Kazial, KA

    2015-01-01

    The objective of the study was to examine salivary biomarker response to fluid consumption in exercising athletes. Exercise induces stress on the body and salivary alpha amylase (sAA) and salivary cortisol are useful biomarkers for activity in the sympathoadrenal medullary system and the hypothalamic pituitary adrenal axis which are involved in the stress response. Fifteen college students were given 150 ml and 500 ml of water on different days and blinded to fluid condition. The exercise protocol was identical for both fluid conditions using absolute exercise intensities ranging from moderate to high. Saliva was collected prior to exercise, post moderate and post high intensities and analyzed by Salimetrics assays. Exercise was significant for sAA with values different between pre-exercise (85 ± 10 U · ml−1) and high intensity (284 ± 30 U · ml−1) as well as between moderate intensity (204 ± 32 U · ml−1) and high intensity. There was no difference in sAA values between fluid conditions at either intensity. Exercise intensity and fluid condition were each significant for cortisol. Cortisol values were different between pre-exercise (0.30 ± 0.03 ug · dL−1) and high intensity (0.45 ± 0.05 ug · dL−1) as well as between moderate intensity (0.33 ± 0.04 ug · dL−1) and high intensity. Moderate exercise intensity cortisol was lower in the 500 ml condition (0.33 ± 0.03 ug · dL−1) compared with the 150 ml condition (0.38 ± 0.03 ug · dL−1). This altered physiological response due to fluid consumption could influence sport performance and should be considered. In addition, future sport and exercise studies should control for fluid consumption. PMID:26681828

  3. Salivary alpha-amylase, secretory IgA and free cortisol as neurobiological components of the stress response in the acute phase of anorexia nervosa.

    PubMed

    Paszynska, E; Dmitrzak-Weglarz, M; Tyszkiewicz-Nwafor, M; Slopien, A

    2016-06-01

    Objectives One novel hypothesis of the pathogenesis of anorexia nervosa (AN) is the possible role of mental stress in hyperactivity of the autonomic nervous system (ANS) and of the hypothalamic-pituitary-adrenal (HPA) axis. Two components of stress response - salivary alpha-amylase (sAA) and free cortisol - have been proposed. They can be determined in saliva, which closely reflects their concentrations in plasma. The purpose of this study was to measure salivary free cortisol, sAA and their correlation to secretory IgA (sIgA) of patients with AN in comparison to the average population. Methods A controlled clinical trial was designed for a matched group of 47 AN patients and 54 healthy individuals. After clinical examination, unstimulated salivary samples were taken during the acute stage of AN (BMI < 15 kg/m(2)) in the first week of hospitalisation. An enzyme-linked immunosorbent assay (ELISA) suitable for measuring sAA, sIgA and free cortisol were used. Results Anorexic patients exhibited disturbances in sAA secretion, and significantly increased cortisol and sIgA levels with a distinct correlation between these two parameters. Conclusions The behaviour of cortisol, sAA and sIgA levels can be assessed as an effect of stress reaction among AN patients with hyperactivity of the HPA axis and ANS dysregulation. The effect of stress response can be assessed reliably in saliva. PMID:26983011

  4. The Multiple Forms of alpha-Amylase Enzyme of the Araucaria Species of South America: A. araucana (Mol.) Koch and A. angustifolia (Bert.) O. Kutz : A Comparative Study.

    PubMed

    Salas, E; Cardemil, L

    1986-08-01

    alpha-Amylase is one of the major enzymes present in the seeds of both Araucaria species of South America and it initiates starch hydrolysis during germination and early seedling growth. The pattern of the multiple forms of alpha-amylase of the two Araucaria species was investigated by electrophoresis and isoelectrofocusing of the native enzyme in polyacrylamide gels. The enzyme forms were compared in the embryo and megagametophyte of quiescent seeds and of seeds imbibed for 18, 48, and 90 hours. Specific alpha-amylase enzyme forms appear and disappear during these imbibition periods showing both similarities and differences between tissues and species. Before imbibition, there are five alpha-amylase forms identical in both tissues, but different between species. After 18 hours of imbibition, there are two enzyme forms in both tissues of Araucaria araucana seeds, only one form in the embryo of Araucaria angustifolia but two forms in the megagametophyte of this specie. After 48 hours of seed imbibition, most of the enzyme forms present in quiescent seeds reappear. At 90 hours of imbibition different enzyme forms are detected in the embryo with respect to the gametophyte. The changes in form patterns of alpha-amylase are discussed according to a possible regulation of gene expression by endogenous gibberellins. PMID:16664944

  5. [The contribution of different alpha-amylase isoenzymes of the commodity grain spring wheat in the formation of falling number values].

    PubMed

    Mamytova, N S; Kuzovlev, V A; Khakimzhanov, A A; Fursov, O V

    2014-01-01

    The participation of various isoenzymes of alpha-amylase in the formation of falling number values of the commodity grain of wheat grown in the Republic of Kazakhstan was investigated. It was found that active isoenzymes alpha-AMY1 and alpha-AMY2 of the embryonic shield were present in the grain with an index over 200. A significant decrease in the falling number depended mainly on the synthesis of alpha-AMY1 and alpha-AMY2 isoenzymes in the aleurone layer. In the grain, isoenzymes with high isoelectric points (p1 > or = 7.3) were found; these isoenzymes belong to alpha-amylase or late maturing or alpha-amylase of practically mature grains. It was discovered that the exogenous hormone (gibberellic acid) induced synthesis of alpha-amylase isoenzymes of scutellum, whole caryopses, and aleurone. It was shown that the impact of exogenous gibberellic acid on the activity and structure of alpha-amylase is reduced in grain with a low falling number. PMID:25707111

  6. Putative implication of alpha-amylase loop 7 in the mechanism of substrate binding and reaction products release.

    PubMed

    André, G; Tran, V

    2004-10-01

    Alpha-amylases are widespread endo-enzymes involved in the hydrolysis of internal alpha-(1,4) glycosidic linkages of starch polymers. Molecular modeling of amylose-amylase interactions is a step toward enzymatic mechanism understanding and rational design of new enzymes. From the crystallographic complex of barley alpha-amylase AMY2-acarbose, the static aspects of amylose-amylase docking have been characterized with a model of maltododecaose (DP12) (G. André, A. Buléon, R. Haser, and V. Tran, Biopolymers 1999, Vol. 50, pp. 751-762; G. André and V. Tran, Special Publication no. 246 1999, The Royal Society of Chemistry, H. J. Gilbert, G. J. Davies, B. Henrissat, and B. Svensson, Eds., Cambridge, pp. 165-174). These studies, consistent with the experimental subsite mapping (K. Bak-Jensen, G. André, V. Tran, and B. Svensson, Journal of Biological Chemistry, to be published), propose a propagation scheme for an amylose chain in the active cleft of AMY2. The topographical overview of alpha-amylases identified loop 7 as a conserved segment flanking the active site. Since some crystallographic experiments suspected its high flexibility, its putative motion was explored through a robotic scheme, an alternate route to dynamics simulations that consume CPU time. The present article describes the characteristics of the flexibility of loop 7: location and motion in AMY2. A back-and-forth motion with a large amplitude of more than 0.6 nm was evaluated. This movement could be triggered by two hinge residues. It results in the loop flipping over the active site to enhance the docking of the native helical substrate through specific interactions, it positions the catalytic residues, it distorts the substrate towards its transition state geometry, and finally monitors the release of the products after hydrolysis. The residues involved in the process are now rational mutation points in the hands of molecular biologists. PMID:15356864

  7. Production of L-Lysine from starch by Corynebacterium glutamicum displaying alpha-amylase on its cell surface.

    PubMed

    Tateno, Toshihiro; Fukuda, Hideki; Kondo, Akihiko

    2007-04-01

    We engineered a Corynebacterium glutamicum strain displaying alpha-amylase from Streptococcus bovis 148 (AmyA) on its cell surface to produce amino acids directly from starch. We used PgsA from Bacillus subtilis as an anchor protein, and the N-terminus of alpha-amylase was fused to the PgsA. The genes of the fusion protein were integrated into the homoserine dehydrogenase gene locus on the chromosome by homologous recombination. L-Lysine fermentation was carried out using C. glutamicum displaying AmyA in the growth medium containing 50 g/l soluble starch as the sole carbon source. We performed L-lysine fermentation at various temperatures (30-40 degrees C) and pHs (6.0-7.0), as the optimal temperatures and pHs of AmyA and C. glutamicum differ significantly. The highest L-lysine yield was recorded at 30 degrees C and pH 7.0. The amount of soluble starch was reduced to 18.29 g/l, and 6.04 g/l L-lysine was produced in 24 h. The L-lysine yield obtained using soluble starch as the sole carbon source was higher than that using glucose as the sole carbon source after 24 h when the same amount of substrates was added. The results shown in the current study demonstrate that C. glutamicum displaying alpha-amylase has a potential to directly convert soluble starch to amino acids. PMID:17216452

  8. Heat shock inhibits. alpha. -amylase synthesis in barley aleurone without inhibiting the activity of endoplasmic reticulum marker enzymes

    SciTech Connect

    Sticher, L.; Biswas, A.K.; Bush, D.S.; Jones, R.L. )

    1990-02-01

    The effects of heat shock on the synthesis of {alpha}-amylase and on the membranes of the endoplasmic reticulum (ER) of barley (Hordeum vulgare) aleurone were studied. Heat shock, imposed by raising the temperature of incubation from 25{degree}C to 40{degree}C for 3 hours, inhibits the accumulation of {alpha}-amylase and other proteins in the incubation medium of barley aleurone layers treated with gibberellic acid and Ca{sup 2+}. When ER is isolated from heat-shocked aleurone layers, less newly synthesized {alpha}-amylase is found associated with this membrane system. ER membranes, as indicated by the activities of NADH cytochrome c reductase and ATP-dependent Ca{sup 2+} transport, are not destroyed by heat stress, however. Although heat shock did not reduce the activity of ER membrane marker enzymes, it altered the buoyant density of these membranes. Whereas ER from control tissue showed a peak of marker enzyme activity at 27% to 28% sucrose (1.113-1.120 grams per cubic centimeter), ER from heat-shocked tissue peaked at 30% to 32% sucrose (1.127-1.137 grams per cubic centimeter). The synthesis of a group of proteins designated as heat-shock proteins (HSPs) was stimulated by heat shock. These HSPs were localized to different compartments of the aleurone cell. Several proteins ranging from 15 to 30 kilodaltons were found in the ER and the mitochondrial/plasma membrane fractions of heat-shocked cells, but none of the HSPs accumulated in the incubation medium of heat-shocked aleurone layers.

  9. Monoclinic crystal form of Aspergillus niger alpha-amylase in complex with maltose at 1.8 angstroms resolution.

    PubMed

    Vujicić-Zagar, A; Dijkstra, B W

    2006-08-01

    Aspergillus niger alpha-amylase catalyses the hydrolysis of alpha-1,4-glucosidic bonds in starch. It shows 100% sequence identity to the A. oryzae homologue (also called TAKA-amylase), three crystal structures of which have been published to date. Two of them belong to the orthorhombic space group P2(1)2(1)2(1) with one molecule per asymmetric unit and one belongs to the monoclinic space group P2(1) with three molecules per asymmetric unit. Here, the purification, crystallization and structure determination of A. niger alpha-amylase crystallized in the monoclinic space group P2(1) with two molecules per asymmetric unit in complex with maltose at 1.8 angstroms resolution is reported. Furthermore, a novel 1.6 angstroms resolution orthorhombic crystal form (space group P2(1)2(1)2) of the native enzyme is presented. Four maltose molecules are observed in the maltose-alpha-amylase complex. Three of these occupy active-site subsites -2 and -1, +1 and +2 and the hitherto unobserved subsites +4 (Asp233, Gly234) and +5 (Asp235). The fourth maltose molecule binds at the distant binding sites d1 (Tyr382) and d2 (Trp385), also previously unobserved. Furthermore, it is shown that the active-site groove permits different binding modes of sugar units at subsites +1 and +2. This flexibility of the active-site cleft close to the catalytic centre might be needed for a productive binding of substrate chains and/or release of products. PMID:16880540

  10. Location of the alpha-amylase gene in rumen Streptococcus bovis strains distinguished by unstable amylase activity.

    PubMed

    Mareková, M; Jonecová, Z; Kmeĭ, V

    1995-01-01

    Genetic stability of amylase activity after serial subcultivation experiments with amylolytic ruminal Streptococcus bovis strains was investigated. Two strains Amy+ and Amy- were obtained. Loss of amylase activity connected with the loss of plasmid DNA was not found in these strains. The presence of the gene responsible for the amylase activity in the chromosome of these strains was revealed by hybridization of the alpha-amylase gene on pJK108 against chromosomal DNA of S. bovis and Bacillus subtilis after a complete restriction with EcoRI. PMID:8851562

  11. Electrospray mass spectrometry characterization of post-translational modifications of barley alpha-amylase 1 produced in yeast.

    PubMed

    Søgaard, M; Andersen, J S; Roepstorff, P; Svensson, B

    1993-10-01

    We have used electrospray mass spectrometry (ESMS) in combination with protein chemistry and genetics to delineate post-translational modifications in yeast of barley alpha-amylase 1 (AMY1), a 45 kD enzyme crucial for production of malt, an important starting material in the manufacture of beer and whisky. In addition to signal peptide processing these modifications are: (1) removal of C-terminal Arg-Ser by Kex1p, (2) glutathionylation of Cys95, (3) O-glycosylation, and (4) additional degradation of the C-terminus. PMID:7764097

  12. High-efficiency, one-step starch utilization by transformed Saccharomyces cells which secrete both yeast glucoamylase and mouse alpha-amylase.

    PubMed Central

    Kim, K; Park, C S; Mattoon, J R

    1988-01-01

    Transformed, hybrid Saccharomyces strains capable of simultaneous secretion of glucoamylase and alpha-amylase have been produced. These strains could carry out direct, one-step assimilation of starch, with conversion efficiency greater than 93% during a 5-day growth period. One of the transformants converted 92.8% of available starch into reducing sugars in only 2 days. Glucoamylase secretion by these strains resulted from expression of one or more chromosomal STA genes derived from Saccharomyces diastaticus. The strains were transformed by a plasmid (pMS12) containing mouse salivary alpha-amylase cDNA in an expression vector containing yeast alcohol dehydrogenase promoter and a segment of yeast 2 micron plasmid. The major starch hydrolysis product produced by crude amylases found in culture broths was glucose, indicating that alpha-amylase and glucoamylase acted cooperatively. PMID:3132104

  13. The structure of barley alpha-amylase isozyme 1 reveals a novel role of domain C in substrate recognition and binding: a pair of sugar tongs.

    PubMed

    Robert, Xavier; Haser, Richard; Gottschalk, Tine E; Ratajczak, Fabien; Driguez, Hugues; Svensson, Birte; Aghajari, Nushin

    2003-08-01

    Though the three-dimensional structures of barley alpha-amylase isozymes AMY1 and AMY2 are very similar, they differ remarkably from each other in their affinity for Ca(2+) and when interacting with substrate analogs. A surface site recognizing maltooligosaccharides, not earlier reported for other alpha-amylases and probably associated with the different activity of AMY1 and AMY2 toward starch granules, has been identified. It is located in the C-terminal part of the enzyme and, thus, highlights a potential role of domain C. In order to scrutinize the possible biological significance of this domain in alpha-amylases, a thorough comparison of their three-dimensional structures was conducted. An additional role for an earlier-identified starch granule binding surface site is proposed, and a new calcium ion is reported. PMID:12906828

  14. Salivary cortisol and alpha-amylase reactivity to taekwondo competition in children.

    PubMed

    Capranica, Laura; Lupo, Corrado; Cortis, Cristina; Chiodo, Salvatore; Cibelli, Giuseppe; Tessitore, Antonio

    2012-02-01

    The aim of this study was to evaluate the effects of an official taekwondo competition (three 1-min rounds with a 1-min recovery in-between) on heart rate (HR), salivary alpha-amylase (sAA), and salivary-free cortisol (sC) in children. Parental consent was obtained for 12 young (10.4 ± 0.2 years) male taekwondo athletes. Saliva sample were collected 15 min before and 1 min after an official taekwondo competition, and at 30, 60, and 90 min of the recovery period. To evaluate the exercise intensity during the competition, HR was measured and expressed as a percentage of individuals HR(peak). Athletes spent 78% of the time working at HR > 90% HR(max), with significant increases from round 1 to round 2 and 3. Peak sAA observed at the end of the match (169.6 ± 47.0 U/mL) was different (P = 0.0001) from the other samplings (pre-competition 55.0 ± 14.0 U/mL, 30-min recovery 80.4 ± 17.7 U/mL, 60-min recovery 50.5 ± 7.6 U/ml; 90-min recovery 53.2 ± 9.6 U/mL). Peak sC values observed at 30-min recovery (17.9 ± 3.5 nmol/L) were different (P < 0.0001) from pre-competition (5.6 ± 0.9 nmol/L), post-competition (9.0 ± 2.0 nmol/L), 60-min recovery (10.3 ± 2.6 nmol/L) and 90-min recovery (4.2 ± 0.8 nmol/L) values. These findings confirm that taekwondo competitions pose a high stress on young athletes. The different sAA and sC reactions in response to the physical stressor mirror the faster reactivity of the sympathetic-adrenomedullary system relatively to the hypothalamic-pituitary-adrenocortical system, respectively. This experimental paradigm might represent a useful model for further research on the effects of various stressors (i.e., training and competition) in taekwondo athletes. PMID:21643917

  15. Alpha-amylase from germinating soybean (Glycine max) seeds--purification, characterization and sequential similarity of conserved and catalytic amino acid residues.

    PubMed

    Kumari, Arpana; Singh, Vinay Kumar; Fitter, Jörg; Polen, Tino; Kayastha, Arvind M

    2010-10-01

    Starch hydrolyzing amylase from germinated soybeans seeds (Glycine max) has been purified 400-fold to electrophoretic homogeneity with a final specific activity of 384 units/mg. SDS-PAGE of the final preparation revealed a single protein band of 100 kDa, whereas molecular mass was determined to be 84 kDa by MALDI-TOF and gel filtration on Superdex-200 (FPLC). The enzyme exhibited maximum activity at pH 5.5 and a pI value of 4.85. The energy of activation was determined to be 6.09 kcal/mol in the temperature range 25-85 degrees C. Apparent Michaelis constant (K(m)((app))) for starch was 0.71 mg/mL and turnover number (k(cat)) was 280 s(-1) in 50 mM sodium acetate buffer, pH 5.5. Thermal inactivation studies at 85 degrees C showed first-order kinetics with rate constant (k) equal to 0.0063 min(-1). Soybean alpha-amylase showed high specificity for its primary substrate starch. High similarity of soybean alpha-amylase with known amylases suggests that this alpha-amylase belongs to glycosyl hydrolase family 13. Cereal alpha-amylases have gained importance due to their compatibility for biotechnological applications. Wide availability and easy purification protocol make soybean as an attractive alternative for plant alpha-amylase. Soybean can be used as commercially viable source of alpha-amylase for various industrial applications. PMID:20655076

  16. Coordinate increase in major transcripts from the high pI alpha-amylase multigene family in barley aleurone cells stimulated with gibberellic acid.

    PubMed

    Rogers, J C; Milliman, C

    1984-10-10

    The purpose of this study was to identify specifically genes and transcripts for the high pI isozyme of barley alpha-amylase. From hybridization of coding sequence probes to blots of genomic DNA digested with restriction enzymes that do not cut within our cloned high pI alpha-amylase cDNA, it is estimated that about 7 alpha-amylase genes or pseudogenes exist. No difference could be detected between barley aleurone cell and sprout DNAs. Experiments using probes from the 5' and 3' untranslated sequences of the high pI alpha-amylase cDNA clone identified three HindIII fragments that probably carry high pI sequences. Primer extension experiments used as a primer the terminal 5' coding sequence from our cDNA clone; this primer would not cross-hybridize to low pI alpha-amylase transcripts. Two major transcripts were identified. These shared a conserved 23-base sequence immediately 5' to the ATG start codon, although a C----G transversion and a 3-base deletion were present within this sequence. An unusual 8-base pair GC palindrome was present in the conserved region immediately preceding the ATG start codon. Distal to the conserved sequence there was no apparent homology. One transcript carrying a 97-base untranslated region was identical to our high pI cDNA clone E. The gene for the other was recovered from a lambda phage genomic library. The 5' coding sequence was very similar, but not identical to clone E, demonstrating that these transcripts arise from separate genes. The two transcripts increased coordinately in aleurone cells stimulated with gibberellic acid. These data indicate that there is a high pI alpha-amylase multigene family with at least two active members, both of which are regulated in some manner by the plant hormone gibberellic acid. PMID:6090459

  17. A Pilot Study of Psychotherapist Trainees’ Alpha-Amylase and Cortisol Levels During Treatment of Recently Suicidal Clients With Borderline Traits

    PubMed Central

    Miller, Grant D.; Iverson, Katherine M.; Kemmelmeier, Markus; MacLane, Chelsea; Pistorello, Jacqueline; Fruzzetti, Alan E.; Crenshaw, Katrina Y.; Erikson, Karen M.; Katrichak, Barrie M.; Oser, Megan; Pruitt, Larry D.; Watkins, Melanie M.

    2010-01-01

    Psychotherapists often experience stress while providing psychotherapy, in particular when working with difficult presentations such as suicidality. As part of a larger study on the treatment of recently suicidal college students with borderline traits, 6 therapists in training collected their own salivary samples for alpha-amylase (AA) and cortisol (C) analyses immediately before and after sessions with 2 selected clients. On average, samples were collected for the same therapist–patient dyad throughout the year-long study to ensure that data reflected therapist responses across stages of treatment. Therapists also completed a working alliance questionnaire and rated perceived session difficulty immediately after each selected session. Contrary to expectations, therapists demonstrated elevated levels of stress as measured by AA and C at presession relative to postsession levels. Greater session difficulty was related to more pronounced declines in AA, whereas a stronger working alliance was linked to more pronounced reductions in C. Results suggest that physiological stress responses while working with recently suicidal clients with borderline traits occur primarily in terms of session anticipatory anxiety, whereas AA and C changes may be affected differently by factors such as session difficulty and working alliance. This is a pilot study, limited by its sample size, but the design, findings, and inclusion of physiological measures present an initial step in an essential line of research. PMID:21709772

  18. Cloning and characterization of a second alpha-amylase gene (LKA2) from Lipomyces kononenkoae IGC4052B and its expression in Saccharomyces cerevisiae.

    PubMed

    Eksteen, Jeremy M; Steyn, Andries J C; van Rensburg, Pierre; Cordero Otero, Ricardo R; Pretorius, Isak S

    2003-01-15

    Lipomyces kononenkoae secretes a battery of highly effective amylases (i.e. alpha-amylase, glucoamylase, isoamylase and cyclomaltodextrin glucanotransferase activities) and is therefore considered as one of the most efficient raw starch-degrading yeasts known. Previously, we have cloned and characterized genomic and cDNA copies of the LKA1 alpha-amylase gene from L. kononenkoae IGC4052B (CBS5608T) and expressed them in Saccharomyces cerevisiae and Schizosaccharomyces pombe. Here we report on the cloning and characterization of the genomic and cDNA copies of a second alpha-amylase gene (LKA2) from the same strain of L. kononenkoae. LKA2 was cloned initially as a 1663 bp cDNA harbouring an open reading frame (ORF) of 1496 nucleotides. Sequence analysis of LKA2 revealed that this ORF encodes a protein (Lka2p) of 499 amino acids, with a predicted molecular weight of 55,307 Da. The LKA2-encoded alpha-amylase showed significant homology to several bacterial cyclomaltodextrin glucanotransferases and also to the alpha-amylases of Aspergillus nidulans, Debaryomyces occidentalis, Saccharomycopsis fibuligera and Sz. pombe. When LKA2 was expressed under the control of the phosphoglycerate kinase gene promoter (PGK1(p)) in S. cerevisiae, it was found that the genomic copy contained a 55 bp intron that impaired the production of biologically active Lka2p in the heterologous host. In contrast to the genomic copy, the expression of the cDNA construct of PGK1p-LKA2 in S. cerevisiae resulted in the production of biologically active alpha-amylase. The LKA2-encoded alpha-amylase produced by S. cerevisiae exhibited a high specificity towards substrates containing alpha-1,4 glucosidic linkages. The optimum pH of Lka2p was found to be 3.5 and the optimum temperature was 60 degrees C. Besides LKA1, LKA2 is only the second L. kononenkoae gene ever cloned and expressed in S. cerevisiae. The cloning, characterization and co-expression of these two genes encoding these highly efficient alpha-amylases

  19. Application of the extracellular alpha-amylase gene from Streptococcus bovis 148 to construction of a secretion vector for yogurt starter strains.

    PubMed

    Satoh, E; Ito, Y; Sasaki, Y; Sasaki, T

    1997-11-01

    Streptococcus thermophilus ATCC 19258, Lactobacillus delbrueckii subsp. bulgaricus T-11, and Lactococcus lactis subsp. lactis IL1403 were transformed with the alpha-amylase gene (amyA) from Streptococcus bovis 148 by using a wide host-range vector, and all the transformants secreted the alpha-amylase successfully. Since the promoter and the secretion signal of the amyA gene were functional in these strains, we constructed a secretion vector using the expression elements of amyA. Trials to secrete foreign enzymes in yogurt starter strains were performed using this novel secretion vector. PMID:9361445

  20. Application of the extracellular alpha-amylase gene from Streptococcus bovis 148 to construction of a secretion vector for yogurt starter strains.

    PubMed Central

    Satoh, E; Ito, Y; Sasaki, Y; Sasaki, T

    1997-01-01

    Streptococcus thermophilus ATCC 19258, Lactobacillus delbrueckii subsp. bulgaricus T-11, and Lactococcus lactis subsp. lactis IL1403 were transformed with the alpha-amylase gene (amyA) from Streptococcus bovis 148 by using a wide host-range vector, and all the transformants secreted the alpha-amylase successfully. Since the promoter and the secretion signal of the amyA gene were functional in these strains, we constructed a secretion vector using the expression elements of amyA. Trials to secrete foreign enzymes in yogurt starter strains were performed using this novel secretion vector. PMID:9361445

  1. N-terminal sequence of amino acids and some properties of an acid-stable alpha-amylase from citric acid-koji (Aspergillus usamii var.).

    PubMed

    Suganuma, T; Tahara, N; Kitahara, K; Nagahama, T; Inuzuka, K

    1996-01-01

    An acid-stable alpha-amylase (AA) was purified from an acidic extract of citric acid-koji (A. usamii var.). The N-terminal sequence of the first 20 amino acids of the enzyme was identical with that of AA from A. niger, but the two enzymes differed in molecular weight. HPLC analysis for identifying the anomers of products indicated that the AA hydrolyzed maltopentaose (G5) at the third glycoside bond predominantly, which differed from Taka-amylase A and the neutral alpha-amylase (NA) from the citric acid-koji. PMID:8824843

  2. Production and characterization of alpha-amylase from mango kernel by Fusarium solani NAIMCC-F-02956 using submerged fermentation.

    PubMed

    Kumar, Devendra; Yadav, Kaushlesh K; Muthukumar, M; Garg, Neelima

    2013-11-01

    Microbial production of enzymes using low valued agro industrial wastes is gaining importance globally. Mango is one of the major fruit processed into a variety of products. During processing 40-50% of solid waste is generated in form of peel and stones. After decortications of mango stone, kernel is obtained which is a rich source of starch (upto 60%). It was utilized as a substrate for alpha-amylase production using Fusarium soloni. Maximum alpha-amylase production (0.889 U g(-1)) was recorded using a substrate concentration of 5% (w/v), pH-4 and temperature 30 degrees C on 9th day of incubation. Supplementation of production medium with micronutrients viz., Ca2+, Fe2+ or Mg2+ improved the enzyme production while, Zn2+, B3+ or Mn2+ ions exhibited inhibitory effect. The extracellular protein was precipitated by ammonium sulphate up to 70% saturation, dialyzed and purified (27.84 fold) by gel-exclusion (Sephadex G-75) chromatography. Protein profiling on 12% SDS-PAGE revealed three bands corresponding to 26, 27 and 30 kDa molecular sizes. The optimum amylase activity was achieved at pH 5.0 at 40 degrees C. The Michaelis constant (KM), Vmax and activation energy (-Ea) were found to be 3.7 mg ml(-1), 0.24 U mg(-1) and 42.39 kJ mole(-1), respectively. PMID:24555336

  3. Improvement in lactic acid production from starch using alpha-amylase-secreting Lactococcus lactis cells adapted to maltose or starch.

    PubMed

    Okano, Kenji; Kimura, Sakurako; Narita, Junya; Fukuda, Hideki; Kondo, Akihiko

    2007-07-01

    To achieve direct and efficient lactic acid production from starch, a genetically modified Lactococcus lactis IL 1403 secreting alpha-amylase, which was obtained from Streptococcus bovis 148, was constructed. Using this strain, the fermentation of soluble starch was achieved, although its rate was far from efficient (0.09 g l(-1) h(-1) lactate). High-performance liquid chromatography revealed that maltose accumulated during fermentation, and this was thought to lead to inefficient fermentation. To accelerate maltose consumption, starch fermentation was examined using L. lactis cells adapted to maltose instead of glucose. This led to a decrease in the amount of maltose accumulation in the culture, and, as a result, a more rapid fermentation was accomplished (1.31 g l(-1) h(-1) lactate). Maximum volumetric lactate productivity was further increased (1.57 g l(-1) h(-1) lactate) using cells adapted to starch, and a high yield of lactate (0.89 g of lactate per gram of consumed sugar) of high optical purity (99.2% of L: -lactate) was achieved. In this study, we propose a new approach to lactate production by alpha-amylase-secreting L. lactis that allows efficient fermentation from starch using cells adapted to maltose or starch before fermentation. PMID:17384945

  4. Structure and molecular model refinement of Aspergillus oryzae (TAKA) alpha-amylase: an application of the simulated-annealing method.

    PubMed

    Swift, H J; Brady, L; Derewenda, Z S; Dodson, E J; Dodson, G G; Turkenburg, J P; Wilkinson, A J

    1991-08-01

    Monoclinic crystals of a neutral alpha-amylase from Aspergillus oryzae, containing three molecules in the asymmetric unit, have been reported previously and studied at 3 A resolution [Matsuura, Kunusoki, Harada & Kakudo (1984). J. Biochem. 95, 697-702]. Here we report the solution of the structure of this enzyme in a different crystal form (space group P2(1)2(1)2(1), a = 50.9, b = 67.2, c = 132.7 A), with only one molecule in the asymmetric unit. The structure was solved by the molecular replacement method, using a model of acid alpha-amylase from a related fungus A. niger [Brady, Brzozowski, Derewenda, Dodson & Dodson (1991). Acta Cryst. B47, 527-535]. Conventional least-squares crystallographic refinement failed to converge in a satisfactory manner, and the technique of molecular dynamics in the form of the XPLOR package [Brunger (1988). XPLOR Manual. Yale Univ., USA] was used to overcome the problem. A large rigid-body type movement of the C-terminal domain was identified and accounted for. The final round of restrained least-squares refinement (at 2.1 A resolution) including 3675 protein atoms and 247 water molecules resulted in a conventional crystallographic R factor of 0.183 and an atomic model which conforms well to standard stereochemical parameters (standard deviation of bond lengths from their expected values is 0.028 A, while that for planar groups is 0.029 A). PMID:1930835

  5. Effects of sorghum (Sorghum bicolor (L.) Moench) tannins on alpha-amylase activity and in vitro digestibility of starch in raw and processed flours

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of condensed tannins (CT) on in vitro starch digestibility in cooked, wholegrain sorghum flours and on corn starch was investigated. CT extracts were also tested for their inhibitory effect on alpha-amylases. Rapidly digestible starch, slowly digestible starch, and resistant starch were n...

  6. MALTOTRIOSE, PRODUCT OF ALPHA-AMYLASE STARCH HYDROLYSIS, SUPPRESSES MALTASE-GLUCOAMYLASE ACTIVITY AND SLOWS TERMINAL STARCH DIGESTION 44.5 FOLD

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starches constitute the main caloric source in the average human diet. The digestion of starches is far more complex than sugars and requires six different enzyme activities to produce free glucose before absorption. Salivary and pancreatic alpha-amylase activities initially hydrolyze internal 1-4 g...

  7. Discovering an Accessible Enzyme: Salivary [alpha]-Amylase--"Prima Digestio Fit in Ore"--A Didactic Approach for High School Students

    ERIC Educational Resources Information Center

    Marini, Isabella

    2005-01-01

    Human salivary [alpha]-amylase is used in this experimental approach to introduce biology high school students to the concept of enzyme activity in a dynamic way. Through a series of five easy, rapid, and inexpensive laboratory experiments students learn what the activity of an enzyme consists of: first in a qualitative then in a semi-quantitative…

  8. Concomitant production of two proteases and alpha-amylase by a novel strain of Bacillus subtilis in a microprocessor controlled bioreactor

    PubMed Central

    Mukhtar, Hamid; Ikram-ul-Haq

    2012-01-01

    We describe the simultaneous production of Bacillus subtilis based proteases and alpha amylase using a computer controlled laboratory scale 7.5 L batch bioreactor. The present strain is the first to be reported that concomitantly produces these two industrially important enzymes. The growth and sporulation of Bacillus subtilis was monitored and maximum production of alkaline protease and alpha amylase was found to coincide with maximum sporulation. Two types of proteases were detected in the fermentation broth; a neutral and an alkaline protease most active in a pH range of 7.0–8.0 and 8.0–10, respectively. Maximum production of proteases was observed at an incubation temperature of 37°C while that of alpha amylase was observed at 40°C. The optimum aeration and agitation levels for protease production were 0.6 L/L/min and 200rpm, respectively, and for alpha amylase were 0.6 L/L/min and 150 rpm. The kinetic parameters Yp/x and qp were also found to be significant at the given fermentation conditions. PMID:24031930

  9. General Subject 2. Report to ICUMSA on the determination of carry-over alpha-amylase activity in white and refined sugars by a spectrophotometric method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A report is given on a new industrial method for the determination of carry-over alpha-amylase activity in raw and refined sugars, as well as a recommendation. In recent years, there has been increased concern over carry-over activity of mostly high temperature (HT) and very high temperature (VHT) s...

  10. Salivary Alpha Amylase and Cortisol Levels in Children with Global Developmental Delay and Their Relation with the Expectation of Dental Care and Behavior during the Intervention

    ERIC Educational Resources Information Center

    dos Santos, Marcio Jose Possari; Bernabe, Daniel Galera; Nakamune, Ana Claudia de Melo Stevanato; Perri, Silvia Helena Venturoli; de Aguiar, Sandra Maria Herondina Coelho Avila; de Oliveira, Sandra Helena Penha

    2012-01-01

    The purpose of this study was to analyze the alpha-amylase (sAA) and cortisol levels in children with Global developmental delay (GDD) before and after dental treatment and its association with the children's behavior during treatment. The morning salivary cortisol levels and activity of sAA of 33 children with GDD were evaluated before and after…