TABLE 1.

Folding yields of wild-type proinsulin and position B8 analogs under three conditions

	pH 7.5 + PDIa	pH 7.5b	pH 10.5c
Wild-type hpid	50%	20%	90%
l-SerB8 hpi (clinical mutation)	15%	Does not fold	90%
d-AlaB8 hpi	60%	40%	90%
l-AlaB8 hpi	Does not fold	Does not fold	Broad peak of folded and misfolded products

^a 10 mm Tris, 10 mm glycine, 1 mm EDTA, 1 mm GSH, 2 mm GSSG, 70 mm GdnHCl, at room temperature with a PDI molar ratio of PDI/proinsulin = 0.093.

^b Same as a without PDI.

^c 50 mm glycine, 1 mm EDTA, 1 mm GSH, 1 mm GSSG, at 4 °C. The polypeptide concentration for all conditions was 0.1 mg/ml. Folded product was indentified by LC-MS. The yields were calculated according to the area under the identified peaks and are ±5%.

^d hpi, human proinsulin.