SMALL MOLECULE CATALYST OF PROTEIN FOLDING

蛋白质二硫键异构酶(PDI)催化的 底物蛋白质中的二硫键。两个Cys-Gly-His-Cys活跃 中心提供低pKa的硫醇和高pKa的二硫键 还原势能(E？？)。 反式-1，20双(2-巯基乙酰胺)环己烷(BMC)模拟PKA和 E？PDI活动站点的。体外试验表明，骨髓基质细胞是 一种高效的重组核糖核酸酶复活催化剂 (核糖核酸酶)A，具有非天然二硫键的底物。活体内 检测结果表明，酵母细胞生长培养液中的BMC可提高酵母细胞的生长速度。 分泌具有八个二硫键的天然酸性磷酸酶。 这一影响类似于中国石油天然气集团公司(PDI)的生产过剩 酵母细胞。BMC，N-甲基-硫代乙酰胺的单硫醇类似物 (NMA)，也催化被扰乱的核糖核酸酶A的重新激活，但更少 比BMC更有效。这些数据表明，具有 低的硫醇PKA和高的二硫键E？？有效地催化了 在蛋白质中形成天然的二硫键。此外，BMC是一种 用于蛋白质体外和体内折叠的有用催化剂 含有多个二硫键。

Protein disulfide isomerase (PDI) catalyzed the interchange of disulfide bonds in substrate proteins. The two Cys-Gly-His-Cys active sites provide a thiol of low pKa and a disulfide bond of high reduction potential (E??). Trans-1,20bis(2-mercaptoacetamido)cyclohexane (BMC) mimics the pKa and E?? of the PDI active sites. In vitro assays demonstrate that BMC is an efficient catalyst of the reactivation of scrambled ribonuclease (Rnase) A, a substrate with non-native disulfide bonds. In vivo assays show that BMC in the growth medium of yeast cells increases the secretion of native acid phosphatase, which has eight disulfide bonds. The effect is similar to that from the overproduction of PDI in the yeast cells. A monothiol analog of BMC, N-methyl-mercaptoacetamide (NMA), also catalyzes the reactivation of scrambled Rnase A, but less efficiently than does BMC. These data indicate that molecules with a low thiol pKa and high disulfide E?? catalyze effectively the formation of native disulfide bonds in proteins. Moreover, BMC is a useful catalyst for the in vitro and in vivo folding of proteins that contain multiple disulfide bonds.