Tang B, Zhang S, Yang K
Institute of Microbiology, Chinese Academy of Sciences, Beijing.
Biochem J. 1994 Jul 1;301 ( Pt 1)(Pt 1):17-20. doi: 10.1042/bj3010017.
Protein disulphide isomerase (PDI) was shown to be able to accelerate the refolding of unfolded recombinant prochymosin and to enhance the overall yield of active protein. Unlike previous reports in this study PDI was found to be active at pH values as high as 11. The coincidence of the similar apparent optimum pH values of uncatalysed and PDI-catalysed reactions suggests that conditions favourable to spontaneous refolding of proteins may help PDI to catalyse thiol/disulphide interchange. Under the conditions described here no exogenously added dithiothreitol was required for PDI-catalysed renaturation, implying that the disulphide form of PDI was reduced to its active form by the free thiol groups in prochymosin molecules.
蛋白质二硫键异构酶（PDI）已被证明能够加速未折叠的重组凝乳酶原的重折叠，并提高活性蛋白的总产量。与本研究之前的报道不同，发现PDI在高达11的pH值下仍具有活性。未催化反应和PDI催化反应的相似表观最佳pH值一致，这表明有利于蛋白质自发重折叠的条件可能有助于PDI催化硫醇/二硫键交换。在此处所述的条件下，PDI催化的复性不需要外源添加二硫苏糖醇，这意味着PDI的二硫键形式被凝乳酶原分子中的游离巯基还原为其活性形式。
