title: X-Prolyl dipeptidyl-aminopeptidase activity, with X-proline p-nitroanilides as substrates, in normal and pathological human sera.
abstract: X-Prolyl dipeptidyl-aminopeptidase (no EC no. assigned) activity in normal and pathological human sera was assayed with several newly synthesized X-proline p-nitroanilides as chromogenic substrates. Normal values for 88 healthy subjects (15 to 81 years old), with glycylproline p-nitroanilide as substrate at pH 8.7, were 54.9 +/- 1.5 (SE) (range, 25.7 - 96.0) mumol/min per liter of serum at 37 degrees C. The results suggest that the enzyme activities with all X-proline p-nitroanilides were increased in patients with hepatitis and decreased in patients with gastric cancer. On Sephadex G-200 column chromatography, normal human sera showed a single peak of enzyme activity with glycylproline p-nitroanilide as the substrate, which coincided with the peak with glycylproline beta-naphthylamide but was different from the peaks with leucine beta-naphthylamide. Sera from patients with hepatitis or liver cirrhosis showed an increase in the normal peak and the appearance of another new peak with glycylproline p-nitroanilide as substrate.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D010450:Endopeptidases / Q000097:blood*; D005260:Female; D006506:Hepatitis A / Q000201:enzymology; D006801:Humans; D007700:Kinetics; D007931:Leucyl Aminopeptidase / Q000097:blood; D008103:Liver Cirrhosis / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D011392:Proline / Q000031:analogs & derivatives / Q000378:metabolism; D012737:Sex Factors
chemical_list: D011392:Proline; D010450:Endopeptidases; D007931:Leucyl Aminopeptidase