succinyl-trialanine-4-nitroanilide and amastatin

Serum succinyl (Ala)3-p-nitroanilide hydrolyzing elastase-like activity which elevates in patients with obstructive jaundice, is due to the joint action of two enzymes: first, succinyl (Ala)3-p-nitroanilide is cleaved to succinyl (Ala)2 and Ala-p-nitroanilide by metalloendopeptidase, and then Ala-p-nitroanilide is cleaved to Ala and p-nitroaniline by aminopeptidase. We adopt a new assay method for serum endopeptidase activity using HPLC.

Topics: Adult; Aminopeptidases; Anti-Bacterial Agents; Cholestasis; Chromatography, High Pressure Liquid; Diabetes Mellitus; Endopeptidases; Female; Glycopeptides; Humans; Immunodiffusion; Kidney; Leucine; Male; Metalloendopeptidases; Neoplasms; Oligopeptides; Peptides; Protease Inhibitors

To elucidate the nature of the abnormality of elastin metabolism in arteriosclerosis, we determined the elastase-type activity in the human radial artery of patients with chronic renal failure due to glomerular disease and diabetes. Elastase-type activity was determined by HPLC analysis of the hydrolyzed products of succinyl-trialanine-4-nitroanilide, a sensitive synthetic substrate for elastase. Three kinds of hydrolyzed products, (L-Ala)2-NA, L-Ala-NA and NA, were found after incubation of the substrate with human radial artery in the presence of amastatin (an inhibitor of aminopeptidases). We assumed the activity that liberates NA to be an elastase-type activity because purified human aorta elastase liberates NA from the substrate. The pH optima of the human artery and rat aorta activities were 6.0 and 6.8, respectively. The elastase activity in human radial artery and rat aorta was inhibited by diisopropyl phosphofluoridate, a serine protease inhibitor, and by elastatinal, an elastase inhibitor. The elastase-type activity in the radial artery of patients with chronic renal failure was significantly lower than that of the control group, and the decrease was especially marked in the patients with juvenile onset diabetes. These results suggest that the elastin metabolism is abnormal in the radial artery in diseases that tend to cause atherosclerosis.

Topics: Adult; Age Factors; Aged; Animals; Anti-Bacterial Agents; Aorta; Arteries; Arteriosclerosis; Chromatography, High Pressure Liquid; Female; Forearm; Humans; Kidney Failure, Chronic; Kinetics; Male; Middle Aged; Oligopeptides; Pancreatic Elastase; Peptides; Rats; Rats, Inbred Strains

Topics: Aged; Anti-Bacterial Agents; Female; Humans; Male; Middle Aged; Neoplasm Invasiveness; Oligopeptides; Pancreatic Elastase; Peptides; Urinary Bladder Neoplasms