Numerous species of insect pests attack cotton plants, out of which the cotton boll weevil (Anthonomus grandis) is the main insect in Brazil and must be controlled to avert large economic losses. Like other insect pests, A. grandis secretes a high level of α-amylases in the midgut lumen, which are required for digestion of carbohydrates. Thus, α-amylase inhibitors (α-AIs) represent a powerful t...

Human salivary amylase and pancreatic amylase were purified and characterized. These amylases gave two bands and one band, respectively, each staining for both protein and sugar, after electrophoresis on sodium dodecyl sulfate--polyacrylamide gel. The relative molecular mass (Mr) or pancreatic amylase was calculated to be 60 000; for the two components (A and B) of salivary amylase the Mr were ...

Amylases catalyze the hydrolysis of starch material and play central roles in carbohydrate metabolism. Compared with many different amylases that are able to hydrolyze only alpha-D-(1,4)-glycosidic bonds, maltogenic amylases exhibit catalytic versatility: hydrolysis of alpha-D-(1,4)- and alpha-D-(1,6)-glycosidic bonds and transglycosylation of oligosaccharides to C3-, C4-, or C6-hydroxyl groups...

The recent state of the knowledge of properties and structure of alpha-amylases is reviewed with the aim of elucidation the basis for their stabilization. Three principal ways for obtaining stable alpha-amylases (isolation of enzymes from extremophiles, production of extremophilic enzymes in mesophiles, and modification of mesophilic enzymes) are discussed separately. Detailed experimental exam...

Two proteins (A-1 and B-2) with -amylase inhibitor activity were extracted and partially purified from Colocasia esculenta tubers through 80% ammonium sulphate fractionation, ion-exchange chromatography on DEAE -Sephacel and gel-chromatography on Sephadex G-100. The molecular weight of A-1 and B-2 were estimated to be about 17000 and 19000 daltons, respectively. The inhibitors inactivated -am...

There are currently 35 available nonredundant molecular structures of class-13 -amylases (EC 3.2.1.1), mostly from microbial organisms living under a wide range of environmental conditions. One of the most recent additions has been the first -amylase structure of a hyperthermophilic archaeon [Linden et al. , J. Biol. Chem. 2003, 278, 9875 ± 9884] . The structure has been used for comparative an...

The addition of gibberellic acid to isolated aleurone layers of barley (Hordeum vulgare L.) causes the production and secretion of four alpha-amylases. Two of these are stable at pH 3.7 and are not inactivated by ethylenediaminetetraacetate. The other two represent the classical barley alpha-amylases; i.e., they are inactivated at pH 3.7 and by reagents which from complexes with divalent metal ...

Midgut hydrolytic enzymes of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) were identified and partially characterized. Km, Vmax, optimum pH, and specific activity were determined for proteolytic enzymes and αamylases. All hydrolytic enzyme activity had an optimum pH value in the alkaline pH range. We observed major serine protease activity, together with minor cysteine-like activity, th...

α-Amylases are widely used enzymes in starch saccharification and baking industries, and in textile desizing. These are endoenzymes which cleave α-1,4-glycosidic linkages randomly in starch, thus, generate maltose and malto oligosaccharides. The commercially available α-amylases have certain limitations like a limited activity at low pH and Ca2+dependence, therefore, the search for novel acid s...

Industrial enzyme market has been projected to reach US$ 6.2 billion by 2020. Major reasons for continuous rise in the global sales of microbial enzymes are because of increase in the demand for consumer goods and biofuels. Among major industrial enzymes that find applications in baking, alcohol, detergent, and textile industries are α-amylases. These are produced by a variety of microbes, whic...