The stability of A1,B29-adipoylinsulin to chemical and enzymatic degradation

The degradation of A1,B29-adipolyinsulin by partial hydrolysis, by disulphide-bond exchange, by chymotrypsin and by a cytosolic enzyme fraction of rat liver was measured and compared with that of A1,B29-diacetylinsulin and insulin. The cross-linked insulin is, in general, more resistant than insulin itself or the diacetylated derivative. However, in the case of enzymatic degradation, A1,B29-diacetylinsulin resembles more the cross-linked derivative than insulin. This provides evidence that the properties of A1,B29-adipoylinsulin could not in all circumstances be attributed to its 'proinsulin-like' structure.