title: The  -amylase of the Beetle Callosobruchus chinensis. Properties.
abstract: C. chinensis larval amylase is activated by Ca(2+) and inhibited by Cl(-) and EDTA (K(i) 6.7x10(-3)m). GSH and 2-mercaptoethanol activate, presumably at different sites, as 2-mercaptoethanol interferes with Ca(2+) activation, whereas GSH enhances it. The inhibition by iodoacetic acid and N-ethylmaleimide (K(i) 1.55x10(-2)m) suggest that free thiol groups are essential for activity. The pH optimum of 5.2-5.4 is moved to 5.6-5.8 by Ca(2+) and 2-mercaptoethanol. The activation energy is 7270 cal/mol, and is not affected by Ca(2+) and 2-mercaptoethanol. K(m) for soluble starch is 2.3mg/ml.
mesh_terms: D000681:Amylases / Q000037:antagonists & inhibitors; D002118:Calcium / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D001517:Coleoptera / Q000201:enzymology*; D004492:Edetic Acid / Q000494:pharmacology; D004789:Enzyme Activation; D005033:Ethylmaleimide / Q000494:pharmacology; D005978:Glutathione / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007461:Iodoacetates / Q000494:pharmacology; D007814:Larva / Q000201:enzymology; D008623:Mercaptoethanol / Q000494:pharmacology; D013696:Temperature
chemical_list: D002712:Chlorides; D007461:Iodoacetates; D008623:Mercaptoethanol; D004492:Edetic Acid; D000681:Amylases; D005978:Glutathione; D005033:Ethylmaleimide; D002118:Calcium