Assays for angiotensin converting enzyme inhibitory activity.
A colorimetric method and a capillary electrophoresis procedure were developed for quantifying histidyl-leucine and hippurate, respectively. The colorimetric method is sensitive (extinction coefficient = 7.5 mM(-1) cm(-1)) and reproducible (CV = 1.7%, n = 5), which is based on a selective chromogenic reaction for histidyl-leucine (lambda(max) = 390 nm) using o-phthalaldehyde. For samples containing unusually high levels of histidine and/or histidyl peptides, the separation-based approach is preferable. The capillary electrophoresis method makes use of an in-capillary microextraction technique; complicated samples can be measured in less than 4 min without pretreatment. Protocols using both methods to measure angiotensin converting enzyme inhibitory activity were proposed.
Chang
B W
BW
Department of Healthcare Administration, Hungkuang Institute of Technology, Taichung, Taiwan, Republic of China
Chen
R L
RL
Huang
I J
IJ
Chang
H C
HC
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000032:analysis*; D000818:Animals; D003124:Colorimetry / Q000379:methods; D004353:Drug Evaluation, Preclinical / Q000295:instrumentation; D019075:Electrophoresis, Capillary / Q000379:methods*; D005658:Fungi; D006626:Hippurates / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D009842:Oligopeptides / Q000032:analysis*; D007703:Peptidyl-Dipeptidase A / Q000032:analysis*; D011817:Rabbits; D015203:Reproducibility of Results; D009764:o-Phthalaldehyde / Q000032:analysis*
D000806:Angiotensin-Converting Enzyme Inhibitors; D006626:Hippurates; D009842:Oligopeptides; D009764:o-Phthalaldehyde; D007703:Peptidyl-Dipeptidase A; C030514:hippuric acid