Abstract
The single chain des(B30) insulin molecule (SCI) was reduced and reoxidized together with porcine proinsulin (PPI). Yields of correctly folded and reoxidized SCI and PPI were analyzed by HPLC [high performance liquid chromatography]. The concentrations of both proteins were 10-3 M during reduction and 10-5 M during oxidation. The pH during reoxidation was varied from 8.6 to 9.2 and the temperature from 4 to 37.degree.. Under all conditions tested, the recovery of SCI was substantially higher than that of PPI. The recoveries peaked after 24-72 h. Apparently the miniproinsulin SCI folds correctly up more efficiently than porcine proinsulin, resulting in higher yields of reoxidized SCI.