Pleiotropic enzyme activities of genetically engineered human prolidase

AIM: To investigate whether the human prolidase possesses the G-type organophosphate hydrolyzing enzyme(Gase) activity besides its ability to catalyze the hydrolysis of the dipeptides bearing a proline residue at the C-terminus. METHODS: Genetic engineering techniques were used in the cloning and expression of the recombinant human prolidase. Prolidase and Gase activities were assayed in the conventional ways. RESULTS: The recombinant human prolidase expressed in COS-7 cells catalyzed the hydrolysis of organophosphorous compound soman as well as the hydrolysis of dipeptide Gly-Pro. Both activities were two-folds higher than that in the non-transformed COS-7 counterpart. Comparison between the two activities in COS-7 cells transfected with the recombinant vector containing the prolidase gene and the control cells showed parallel elevation with a constant ratio. CONCLUSION: It is infered that the Gase and the prolidase are of the same enzyme, or at least belong to isozyme.