Measurement of kallikrein activity in urine of rats and man using a chromogenic tripeptide substrate. Validation of the amidolytic assay by means of bradykinin radioimmunoassay.
Urinary kallikrein activity in rats and man was measured by an amidolytic assay using the chromogenic tripeptide D-valyl-leucyl-arginine-p-nitroanilide (S 2266). The sensitivity of the assay permits the measurement of 3.5 to 250 mKU of purified porcine pancreatic kallikrein. The intraassay coefficient of variation was 1.6 +/- 0.3% and the interassay coefficient of variation 7.4 +/- 0.9%. No changes in kallikrein activity was found in urine samples kept for 7 days at 4 degrees C for 14 months at -20 degrees C. Repeated freezing and thawing reduced kallikrein activity. Kallikrein activity of the same urine samples was also estimated by means of a bradykinin radioimmunoassay, which determines the kinins released during incubation of urine with partially purified dog kininogen (kininogenase activity). The urinary kallikrein activity assayed by means of these two methods showed a high correlation with coefficients of r = 0.9134 for rat urine (p less than 0.0001) and r = 0.8002 for human urine (p less than 0.001).
D000577:Amides / Q000378:metabolism; D000818:Animals; D001920:Bradykinin / Q000032:analysis; D002384:Catalysis; D002863:Chromogenic Compounds; D005615:Freezing; D006801:Humans; D006868:Hydrolysis; D007610:Kallikreins / Q000652:urine*; D009842:Oligopeptides; D011863:Radioimmunoassay; D051381:Rats
D000577:Amides; D002863:Chromogenic Compounds; D009842:Oligopeptides; C031006:Val-Leu-Arg-p-nitroanilide; D007610:Kallikreins; D001920:Bradykinin