Substrate Specificity of Aqualysin I, a Bacterial Thermophilic Alkaline Serine Protease from<i>Thermus aquaticus</i>YT-1: Comparison with Proteinase K, Subtilisin BPN′ and Subtilisin Carlsberg
作者:Terumichi TANAKA、Hiroshi MATSUZAWA、Takahisa OHTA
DOI:10.1271/bbb.62.2161
日期:1998.1
Aqualysin I is the alkaline serine protease isolated from an extreme thermophile, Thermus aquaticus YT-1. We analyzed kinetic properties of aqualysin I, using sixteen kinds of chromogenic succinyl-tripeptide p-nitroanilides as substrates. And we compared the substrate specificity of aqualysin I with those of proteinase K, subtilisin BPN′, and subtilisin Carlsberg. We found that aqualysin I had three subsites, S1, S2, and S3, in the substrate binding site. S1 site preferred alanine and phenylalanine. S2 site preferred alanine and norleucine. And S3 site preferred phenylalanine and isoleucine. These specificities were similar to those of proteinase K and subtilisin BPN′. The specificity of subtilisin Carlsberg differed from those of other enzymes.
Aqualysin I 是从极端嗜热菌栖热菌 YT-1 中分离出来的碱性丝氨酸蛋白酶。我们以 16 种显色琥珀酰三肽对硝基苯胺为底物,分析了 aqualysin I 的动力学性质。我们还比较了 aqualysin I 与蛋白酶 K、枯草杆菌蛋白酶 BPN' 和枯草杆菌蛋白酶 Carlsberg 的底物特异性。我们发现 aqualysin I 在底物结合位点上有 3 个亚位点:S1、S2 和 S3。 S1位点优选丙氨酸和苯丙氨酸。 S2位点优选丙氨酸和正亮氨酸。而S3位点优选苯丙氨酸和异亮氨酸。这些特异性与蛋白酶 K 和枯草杆菌蛋白酶 BPN' 相似。嘉士伯枯草杆菌蛋白酶的特异性不同于其他酶。