Inouye K, Mazda N, Kubo M
Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Japan.
Biosci Biotechnol Biochem. 1998 Apr;62(4):798-800. doi: 10.1271/bbb.62.798.
In thermolysin, tryptophan 115 seems to be at the S2 subsite. Trp-115 was replaced with tyrosine, phenylalanine, leucine, and valine during site-directed mutagenesis in order to evaluate the role of Trp-115 in the proteolytic activity of thermolysin. The mutant enzymes with Tyr-115 or Phe-115 had as much proteolytic activity as the wild-type enzyme, but the other two mutant enzymes had no activity. We found earlier that the substitution of Trp-115 with alanine, glutamic acid, lysine, and glutamine causes the enzyme to lose all activity, so an aromatic amino acid at position 115 seems to be essential for thermolysin.
在嗜热菌蛋白酶中，色氨酸115似乎位于S2亚位点。在定点诱变过程中，色氨酸-115被酪氨酸、苯丙氨酸、亮氨酸和缬氨酸取代，以评估色氨酸-115在嗜热菌蛋白酶蛋白水解活性中的作用。含有酪氨酸-115或苯丙氨酸-115的突变酶具有与野生型酶一样多的蛋白水解活性，但其他两种突变酶没有活性。我们早些时候发现，用丙氨酸、谷氨酸、赖氨酸和谷氨酰胺取代色氨酸-115会导致该酶失去所有活性，因此115位的芳香族氨基酸似乎对嗜热菌蛋白酶至关重要。
