Lau K K, Fong W P
Department of Biochemistry, Chinese University of Hong Kong, Shatin, N.T., Hong Kong.
Biochem Mol Biol Int. 1996 Dec;40(6):1095-103. doi: 10.1080/15216549600201733.
Limited proteolysis of grass carp alcohol dehydrogenase by alkaline protease or subtilisin BPN' at 30 degrees C for 6 hr generated a nicked species that was catalytically active. Electrophoresis on a denaturing SDS-PAGE showed that the 40 kDa subunit of the intact enzyme was cleaved to produce subunits of 27 and 13 kDa, which remained tightly associated with each other under native condition. Such a proteolytically nicked form was catalytically more active than the original intact form of the enzyme. The Vmax value toward the oxidation of ethanol at pH 10 increased by 7.8 fold whereas the K(m) value also exhibited a 140 fold increase. On the other hand, when the same protease treatment was applied to horse liver alcohol dehydrogenase, no activation nor any specific cleavage can be observed.
在30℃下用碱性蛋白酶或枯草杆菌蛋白酶BPN'对草鱼乙醇脱氢酶进行6小时的有限蛋白水解，产生了一种有催化活性的带切口物种。在变性SDS-PAGE上进行电泳显示，完整酶的40 kDa亚基被切割产生27 kDa和13 kDa的亚基，在天然条件下它们彼此紧密结合。这种经蛋白水解产生的带切口形式在催化活性上比酶的原始完整形式更高。在pH 10时对乙醇氧化的Vmax值增加了7.8倍，而K(m)值也增加了140倍。另一方面，当对马肝乙醇脱氢酶进行相同的蛋白酶处理时，未观察到激活现象或任何特异性切割。
