二硫键异构酶的纯化及其对重组蛋白体外折叠的影响

Effects of the Protein Disulfide Isomerase on the Refolding of Recombinant Proteins in vitro

自牛肝中纯化了蛋白二硫键异构酶，并对重组蛋白 的酶促折叠的过程进行了探讨。结果表明，在等摩尔ＰＤＩ的催化作用下，可使１ｍｇ／ｍｌ的ＩＬ－２的正确折叠率提高５８％以上，比活性由４×１０＾６ｕ／ｍｇ增加到８．２×１０＾６ｕ／ｍｇ；ＰＤＩ还能部分纠正二硫键锚配的Ｌ－２异构体成为正确折叠的ＩＬ－２和防止ＩＬ－２通过Ｃｙｓ的链间交联形成聚合体。ＧＭ－ＣＳＦ在ＰＤＩ催化下也有类似的结果。

To increase ratio of correctly folded recombinant proteins, we purified the protein disulfide isomerase (PDI) from bovine liver, and studied the effects of enzyme catalyzed refolding process. Our results indicate that the correct folding ratio of IL-2 increased from 30% to 58% under the action of equal molar of PDI,with the specific activity of IL-2 increased from 4×106u/mg to 8.2×106u/mg. PDI can also partially correct the mismatched IL-2 molecules to the correct folding status and further more, PDI can prevent the formation of oligomer due to interchain disulfide bonds. With similar mechanism. PDI can increase the specific activity of GM-CSF.