Lenney J F
J Bacteriol. 1975 Jun;122(3):1265-73. doi: 10.1128/jb.122.3.1265-1273.1975.
Baker's yeast was found to contain inhibitors of yeast proteases A and C. These two proteins were partially purified, characterized, and compared with the previously described inhibitor of protease B. The A and B inhibitors were very thermostable and were extracted from intact yeast cells at 9k C. The A inhibitor appeared to be a protein with a molecular weight of about 22,000 which could be dissociated into two monomers or chains, both of which had a molecular weight of approximately 11,000. The protease C (carboxypeptidase Y)-inhibitor complex was purified and then partially disociated on an ion-exchange column. The free protease C inhibitor was very unstable, possibly because of destruction by a contaminating protease. Each inhibitor was specific for its corresponding protease and each inhibition was competitive. Whereas proteases A, B, and C destroyed the B inhibitor, only protease B had a pronounced destructive effect on the protease A inhibitor. Pepstatin was found to be a selective inhibitor of protease A, whereas chymostatin and antipain specifically inhibited protease B.
人们发现面包酵母中含有酵母蛋白酶A和C的抑制剂。这两种蛋白质经过了部分纯化、特性鉴定，并与之前描述的蛋白酶B抑制剂进行了比较。A和B抑制剂都具有很高的热稳定性，可在9℃下从完整的酵母细胞中提取出来。A抑制剂似乎是一种分子量约为22,000的蛋白质，它可以解离成两个单体或链，这两个单体或链的分子量都约为11,000。蛋白酶C（羧肽酶Y）-抑制剂复合物被纯化，然后在离子交换柱上部分解离。游离的蛋白酶C抑制剂非常不稳定，可能是因为被一种污染性蛋白酶破坏。每种抑制剂对其相应的蛋白酶都具有特异性，且每种抑制作用都是竞争性的。蛋白酶A、B和C会破坏B抑制剂，而只有蛋白酶B对蛋白酶A抑制剂有明显的破坏作用。人们发现胃蛋白酶抑制剂是蛋白酶A的选择性抑制剂，而胰凝乳蛋白酶抑制剂和抗痛素则特异性抑制蛋白酶B。
