Borgia P T, Campbell L L
J Bacteriol. 1978 May;134(2):389-93. doi: 10.1128/jb.134.2.389-393.1978.
The alpha-amylases from five strains of Bacillus amyloliquefaciens were compared to determine whether differences in primary structure are responsible for variations in catalytic properties previously reported among the enzymes. Amino acid analysis established virtually identical compositions for the proteins. Reaction with dimethylaminoaphthylene sulfonylchloride indicated the amino-terminal amino acid of each amylase to be valine. Carboxyl termini of the enzymes have been determined by digestion with carboxypeptidase A. The resulting kinetic data indicate tyrosine as the carboxyl terminus and leucine as the penultimate residue for all five proteins. Isoelectric focusing of the enzymes yielded isoelectric points in the pH range of 5.09 to 5.18. Tryptic digests of the enzymes chromatographed on a cation-exchange column showed identical elution patterns. It is concluded that the primary structure of the amylase from the five strains is identical or exhibits only conservative substitutions.
比较了五株解淀粉芽孢杆菌的α-淀粉酶，以确定一级结构的差异是否是先前报道的这些酶催化特性变化的原因。氨基酸分析表明这些蛋白质的组成几乎相同。与二甲基氨基萘磺酰氯反应表明每种淀粉酶的氨基末端氨基酸为缬氨酸。通过用羧肽酶A消化来确定酶的羧基末端。所得动力学数据表明所有五种蛋白质的羧基末端为酪氨酸，倒数第二个残基为亮氨酸。这些酶的等电聚焦产生的等电点在pH 5.09至5.18范围内。在阳离子交换柱上进行色谱分析的这些酶的胰蛋白酶消化物显示出相同的洗脱模式。得出的结论是，来自这五株菌株的淀粉酶的一级结构相同或仅表现出保守性取代。
