SPECIFICITY OF PSEUDOMONAS-AERUGINOSA SERRALYSIN REVISITED, USING BIOLOGICALLY-ACTIVE PEPTIDES AS SUBSTRATES

The characterization of the specificity of alkaline protease from Pseu domonas aeruginosa has not yet been clearly defined. Some previous res ults suggested that its specificity was influenced more by amino acids far from the hydrolyzed peptide bond, than by amino acids in P-1 or P '(1) position. From other data, it was a C-(COOH)-type endoprotease wh ere the preferential amino acid in P-1 position was an arginine residu e. We have studied the hydrolysis of several biologically active pepti des. Many various sites of cleavage have been characterized but no arg inine in P1 position was found, despite the presence of arginine in th e peptide sequence. In fact P-1 and P'(1) position could be occupied b y various amino acids. It seems unlikely that Pseudomonas alkaline pro tease may only be considered as a protease specific to arginine in P-1 position. On the other hand, we have observed that increase of the pe ptide chain length led to an important increase of the hydrolysis rate , suggesting an extended number of subsites. (C) 1998 Elsevier Science B.V. All rights reserved.