An assay for angiotensin-converting enzyme using capillary zone electrophoresis

A sensitive and rapid method was developed for angiotensin-converting enzyme (ACE) activity determination by capillary zone electrophoresis, Hippuryl-L-histidyl-L-leucine, a synthetic tripeptide, was used as the;ACE-specific substrate. Capillary zone electrophoresis was employed to separate the products of the enzymatic reaction and the ACE activity was determined by quantification of hippuric acid, a result of the enzymatic reaction on the tripeptide. The capillary electrophoresis was performed in a 27 cm x 75 mu m i.d. fused-silica capillary using 200 mM boric acid-borate:buffer (pH 9.0) as a run buffer with an applied voltage of 8.1 kV at a capillary temperature of 23 degrees C, The electrophoresis was monitored at 228 nm. Each electrophoretic run requires only a nanoliter of the enzymatic reactant solution, at only 6 min, rendering a powerful tool for the ACE assay. (C) 2000 Academic Press.