Pyrrolidone carboxylyl peptidase

Pyrrolidone carboxylyl peptidase activity has been followed using pyrrolidone carboxylyl L-alanine (or other pyrrolidone carboxylyl-amino acids) as substrate by following the amount of amino acid released as determined by the ninhydrin method (137). In another assay procedure the release of -naphthyl amine from L-pyrrolidone carboxylic-/ -naphthylamide (135) is determined by the diazotization procedure of Bratton and Marshall (138) as modified by Goldberg and Rutenberg (139). 

Pyrrolidone carboxylyl peptidase from B. subtilis 135) exhibits properties similar to the enzyme obtained from Pseudomonas. It is of interest that the enzyme is inactivated by shaking with air at room temperature for 5 min and that reactivation is readily achieved by brief incubation with 2-mercaptoethanol and EDTA. 

Studies on pyrrolidone carboxylyl peptidase have shown that the enzyme can catalyze the removal of the terminal pyrrolidone carboxylyl residue from fibrinopeptides, fibrinogen (135, llfi), and human seromu-coid (135). 

A recent report describes the presence of pyrrolidone carboxylyl peptidase in rat liver (46). A partial purification of the enzyme has been obtained by ammonium sulfate fractionation and gel filtration on Sepha-dex G-200. The rat liver enzyme is similar to that obtained from Pseudomonas thus, it is protected against inactivation by 2-pyrrolidone and exhibits similar substrate specificity. 

Exterkate, F. A. (1977). Pyrrolidone carboxylyl peptidase in Streptococcus cremoris Dependence on the interaction with membrane components. J. Bacteriol. 129,1281-1288. 

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