Purification of an 80,000-M(r) glycylprolyl peptidase from Bacteroides gingivalis

An enzyme from Bacteroides gingivalis SUNYAB A7A1-28 that hydrolyzes the synthetic peptide glycyl-L-proline 4-methoxy-β-naphthylamide was purified 1,040-fold by urea extraction, gel filtration, ion-exchange chromatography, and fast protein liquid chromatography. The molecular weight of the enzyme was 80,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 75,000 as determined by gel filtration. The optimum pH for the hydrolysis of glycyl-L-proline 4-methoxy-β-naphthylamide was 7.5 to 8.5. The enzyme activity was inhibited by the serine protease inhibitors diisopropyl fluorophosphate and phenylmethylsulfonyl fluoride by 82.5 and 78%, respectively. The activity was also inhibited by Hg²⁺ (55.6%) and Zn²⁺ (45%).