[Rapid method of measuring angiotensin converting enzyme activity in blood]

A simple and rapid spectrophotometric procedure is developed for measuring the activity of angiotensin-converting enzyme (ACE) in human serum. Furylacryloyl-phenylalanyl-glycyl-glycine (FAPGG) possessing a high absorption capacity at 334 nm was used as the substrate. ACE hydrolyzes FAPGG and decreases the extinction. The level of extinction drop is the measure of ACE activity. Optimal parameters of the enzymatic reaction are defined, including medium pH, substrate concentration, and volumes of the sample and inhibitor of ACE activity. Adequate control permits monitoring the interference of exogenic and endogenic factors in ACE activity in the studied sample. The proposed method is available for clinical laboratories, easily reproducible, and sufficiently sensitive.