Substrate specificity of elastolytic and nonelastolytic proteinases from Pseudomonas aeruginosa

The points of cleavage of oxidized insulin B chain by nonelastolytic alkaline proteinase and elastase from Pseudomonas aeruginosa were compared. The two enzymes showed different specificities. The alkaline proteinase mainly split on the carboxyl side of bonds containing asparagine, cysteic acid, glycine, glutamic acid, tyrosine, arginine, and phenylalanine, whereas the elastase split the bonds containing carboxyl groups of histidine, alanine, tyrosine, leucine, glycine, phenylalanine, and lysine. The alkaline proteinases from different strains showed no differences in specificity. The correlation between elastolysis and substrate specificity is discussed.