Elastolytic proteinases

It has already been remarked that most enzymes with elastolytic activity have proved to be proteinases with a wide peptide-bond specificity. Thus papain, bromelin, and ficin have a similarly broad hydrolytic action and are all active elastolytic enzymes. Sanger et al. (1955) found that the oxidized A chain of insulin was hydrolyzed in a variety of positions by either crude papain or activated mercuripapain. There were five major... 

A second elastolytic enzyme (Af, 21,900) has been isolated from porcine pancreas. It shows higher activity than chymotrypsin in the hydrolysis of acetyltyrosine ester, which is used routinely to assay chymotrypsin. Another E,-like enzyme, a-lytic proteinase (Af, 19,900, 198 amino acids) has been isolated from the soil bacterium Myxobacter 495. This enzyme is remarkably similar to pancreatic E. both in structure (41 % homology, sequence in the active center Gly-Asp-Ser-Gly, 3 homologous disulfide bridges) and substrate specificity. Another E. (Af, 22,300) has been isolated from Pseudomonas aeruginosa. 

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