title: [Participation of ions and solutes on the thermostability of alpha-amylase].
abstract: Supplement effects of ions, sugars, and amino acids on the thermostability of liquefying type alpha-amylase from Bacillus subtilis were examined. The addition of 1 mmol/L Ca2+ or about 50 mmol/L Na+ remarkably stimulated the thermostability of this enzyme among ions examined. The thermostability of the enzyme was enhanced and reduced by the extrinsic addition of 50 mmol/L acidic amino acid such as glutamic acid and alkaline amino acid of the concentrations of sugars from 0 to 1000 mmol/L the thermostability of alpha-amylase increased almost such as arginine, respectively. With the increases linearly. By the co-existence of Na+ or K+ with some amino acids or sugars the thermostability of this enzyme was fairly increased. The changes in the fluorescence intensity of alpha-amylase were examined as a function of the incubation temperature on the enzyme, which showed a good agreement with those of residual activities.
authors.affiliation: Institute of Marine Environmental Protection, SOA, P.O. Box 303, Dalian 116023, China. wangyaobing@vip.sina.com
authors.forename: Yao-Bing
authors.initials: YB
authors.lastname: Wang
authors.forename: Shinichi
authors.initials: S
authors.lastname: Nagata
mesh_terms: D000596:Amino Acids / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002241:Carbohydrates / Q000494:pharmacology; D004795:Enzyme Stability; D011487:Protein Conformation; D012964:Sodium / Q000494:pharmacology; D013696:Temperature; D000516:alpha-Amylases / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000596:Amino Acids; D002241:Carbohydrates; D012964:Sodium; D000516:alpha-Amylases; D002118:Calcium