Mannervik B, Axelsson K, Sundewall A C, Holmgren A
Biochem J. 1983 Aug 1;213(2):519-23. doi: 10.1042/bj2130519.
Two enzyme systems capable of reducing disulphide bonds both in low-Mr compounds and in polypeptides and proteins exist. One consists of thioltransferase in combination with reduced glutathione and glutathione reductase, and the second consists of thioredoxin in combination with thioredoxin reductase. Their relative effectiveness in catalysing disulphide reduction of various substrates in rat liver cytosol was evaluated in the present study. The thioltransferase-dependent system was found to be more efficient in reducing small molecules. Insulin was most effectively reduced by the thioredoxin system. Bovine trypsin was a better substrate for thioltransferase, and partially proteolysed bovine serum albumin was equally good for the two systems. Thus, in the case of protein disulphide bonds, the nature of the particular substrate used determines which of the two reducing systems is the more important.
存在两种能够还原低分子量化合物以及多肽和蛋白质中二硫键的酶系统。一种由硫醇转移酶与还原型谷胱甘肽和谷胱甘肽还原酶组成，另一种由硫氧还蛋白与硫氧还蛋白还原酶组成。本研究评估了它们在催化大鼠肝细胞溶胶中各种底物二硫键还原方面的相对有效性。发现硫醇转移酶依赖性系统在还原小分子方面更有效。胰岛素被硫氧还蛋白系统最有效地还原。牛胰蛋白酶是硫醇转移酶的更好底物，部分蛋白酶解的牛血清白蛋白对这两种系统同样适用。因此，对于蛋白质二硫键而言，所使用的特定底物的性质决定了两种还原系统中哪一种更重要。
