Vukelić B, Ritonja A, Renko M, Pokorny M, Vitale L
Department of Organic Chemistry and Biochemistry, Ruder Bosković Institute, Zagreb, Croatia.
Appl Microbiol Biotechnol. 1992 May;37(2):202-4. doi: 10.1007/BF00178171.
A purification procedure for an extracellular alpha-amylase from Streptomyces rimosus, oxytetracycline-producing strain, is described. The enzyme obtained was shown to be an acidic (pI 4.75) monomer with a relative molecular mass (M(r)) of 43,000, containing three cysteines involved in the catalytic activity of the enzyme. Its amino-terminal part has 57-67% homology with amylases from other Streptomyces species. S. rimosus alpha-amylase is sensitive to higher temperatures, and partially stabilized by Ca2+ ions. It hydrolyses starch (optimum at pH 5.0-6.0) in an endohydrolase manner giving rise to maltotriose, maltotetraose and higher oligosaccharides. Starch granules, except those from rice, were not significantly affected by the isolated alpha-amylase.
本文描述了一种从产土霉素的龟裂链霉菌中纯化细胞外α-淀粉酶的方法。所获得的酶为酸性（pI 4.75）单体，相对分子质量（M(r)）为43,000，含有三个参与酶催化活性的半胱氨酸。其氨基末端部分与其他链霉菌属物种的淀粉酶具有57-67%的同源性。龟裂链霉菌α-淀粉酶对较高温度敏感，并部分受Ca2+离子稳定。它以内切酶方式水解淀粉（最适pH为5.0-6.0），产生麦芽三糖、麦芽四糖和更高的寡糖。除水稻淀粉颗粒外，分离出的α-淀粉酶对其他淀粉颗粒无显著影响。
