Both prolidase and prolinase from the human prostate were separated into two peaks by TSK DEAE-5PW chromatography. These peaks of prolidase isozymes I and II differed from each other in their responses to preincubation with Mn2+, their substrate specificity, optimal pH, and heat stability. The molecular weights of prolidases I and II were estimated to be 110,000 and 165,000, respectively, by gel filtration. Substrate specificity of prolinase peaks I and II was almost the same, but they differed in optimal pH and heat stability. The molecular weights of prolinases I and II were about 85,000 and 63,000, respectively. These results indicate that two isozymes of prolidase and of prolinase, which differ in various characteristics, are present in the human prostate.</p
