Separation of intermediates in the refolding of reduced erabutoxin b by analytical isoelectric focusing in layers of polyacrylamide gel

Isoelectric focusing in a thin layer of polyacrylamide gel is shown to be a suitable method for the resolution of intermediates trapped during the refolding process of reduced cystine-containing proteins. The method has been applied to the well-characterized snake neurotoxin erabutoxin b. An explanation is offered for the relatively low rate of refolding of this polypeptide.