Ubuka T
Department of Biochemistry, Okayama University Medical School, Japan.
Biochem Mol Biol Int. 1996 May;38(6):1103-10.
Renaturation of modified ribonuclease A by protein disulfide isomerase was studied. The renaturation rate of fully S-thiolated ribonuclease A with glutathione, namely, ribonuclease A-glutathione mixed disulfide (RNase-SG) containing 8 moles of glutathione per mole of ribonuclease A (RNase-SG8), by protein disulfied isomerase (PDI) was more than three times faster than those of fully S-thiolated RNase with L-cysteine and scrambled ribonuclease A. Renaturation of RNase-SG species containing 7 or less glutathione was slower than that of RNase-SG8. These data seems to favor the hypothesis that S-thiolation of nascent proteins with glutathione may occur in the folding process during protein synthesis. The applicability of the present method consisted of chemical S-thiolation and PDI-catalyzed renaturation to the in vitro folding of recombinant cysteine-containing proteins is discussed.
研究了蛋白质二硫键异构酶对修饰核糖核酸酶A的复性作用。蛋白质二硫键异构酶（PDI）对每摩尔核糖核酸酶A（RNase-SG8）含有8摩尔谷胱甘肽的完全S-硫醇化核糖核酸酶A与谷胱甘肽，即核糖核酸酶A-谷胱甘肽混合二硫化物（RNase-SG）的复性速率，比完全S-硫醇化的核糖核酸酶与L-半胱氨酸以及混乱型核糖核酸酶A的复性速率快三倍以上。含有7个或更少谷胱甘肽的RNase-SG物种的复性比RNase-SG8慢。这些数据似乎支持这样一种假说：在蛋白质合成过程中的折叠过程中，新生蛋白质可能会与谷胱甘肽发生S-硫醇化。讨论了本方法（包括化学S-硫醇化和PDI催化的复性）在含半胱氨酸重组蛋白体外折叠中的适用性。
