牛肝二硫键异构酶的纯化及其对重组人粒/单系集落刺激因子体外折叠作用的研究

Studies on Purification of Protein Disulfide Isomerase from Bovine Liver and Its Effect on the Refolding of rhGM-CSF in vitro

自牛肝中纯化二硫键异构酶（PDI）。经匀浆、热沉淀、硫酸铵分级分离、阳离子和阴离子交换层析等步骤，得到了比活950U／g电泳纯的PDI。在此基础上研究了PDI对重组人粒／单系集落刺激因子（rhGM－CSF）体外复性作用。结果表明，在PDI与rhGM－CSF摩尔比为2：1时，可使0．5mg／ml的rhGM－CSF正确折叠率提高到60％，比活性由5．0×106U／mg提高到1．0×107U／mg。

Protein disulfide isomerase (PDI) was purified from bovine liver. By means of homogeniza-tion in Triton, heat treatment, ammonium sulfphate fractionation, cation and anion exchange chro-matography, PDI of electroPhoretic purity was obtained, and its specific activity was of 950 U/g.Based on the purification, we studied the effect of PDI on the refolding of rhGM-CSF ic vitro. The re-sults confirmed that the correct folding ratin of rhGM-CSF of 0.5 mg/ml reached from 30% to 60%under the action of two-fold molar of PDI, with the specific activity of rhGM-CSF increased from 5.0×106 U/mg to 1. 0×107 U/mg.