Action of human lysosomal elastase on the oxidized B chain of insulin.

The specificity of action of the lysosomal elastase of human neutrophil leucocytes on the oxidized B chain of insulin is similar to that of pig pancreatic elastase, but is more directed towards valine than alanine as the residue contributing the carboxyl group of the cleaved bond. The most susceptible bonds are Val-12-Glu-13 and Val-18-Cys(O3H)-19. Other bonds hydrolysed are Ala-14-Leu-15, Ser-9-His-10 and Cys, (O3H3)-7-Gly-8. Tables listing amino acid composition, N-terminal residue, and yields of isolated peptides have been deposited as Supplementary Publication SUP 50 075 (8 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1977) 161, 1.