Wang C C
National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, 15 Datun Road, Beijing 100101, China.
Biochemistry (Mosc). 1998 Apr;63(4):407-12.
Protein disulfide isomerase (PDI) is not only an isomerase catalyzing the formation of native disulfide bond(s) of nascent peptide, but also a molecular chaperone assisting chain folding. The intrinsic chaperone activity of PDI is independent of its isomerase activity as shown by its ability of promoting in vitro reactivation and suppressing aggregation during refolding of denatured proteins containing no disulfide. The -CGHC- active sites of PDI are not required for its chaperone activity and a mutant PDI with no isomerase activity does function in vitro and in vivo. The peptide binding site of PDI is responsible for its chaperone activity. Both isomerase and chaperone activities are required for PDI to function as a foldase in assisting protein folding, in other words, the foldase activity of PDI consists of both isomerase and chaperone activities.
蛋白质二硫键异构酶（PDI）不仅是一种催化新生肽天然二硫键形成的异构酶，也是一种协助链折叠的分子伴侣。PDI的内在伴侣活性与其异构酶活性无关，这一点已通过其在体外促进无二硫键的变性蛋白复性过程中的再活化能力以及抑制聚集的能力得到证明。PDI的-CGHC-活性位点对于其伴侣活性并非必需，并且一种没有异构酶活性的突变型PDI在体外和体内均具有功能。PDI的肽结合位点负责其伴侣活性。异构酶和伴侣活性对于PDI作为折叠酶协助蛋白质折叠发挥功能都是必需的，换句话说，PDI的折叠酶活性由异构酶和伴侣活性共同组成。
