Assays for Angiotensin Converting Enzyme Inhibitory Activity

• Published in: Analytical biochemistry Vol. 291; no. 1; pp. 84 - 88
• Main Authors: Chang, Bin-Wha, Chen, Richie L.C., Huang, I-Jen, Chang, Hsien-Chang
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2001
• Subjects: angiotensin converting enzyme; Angiotensin-Converting Enzyme Inhibitors - analysis; Animals; capillary electrophoresis; Colorimetry - methods; Drug Evaluation, Preclinical - instrumentation; Electrophoresis, Capillary - methods; Fungi; hippurate; Hippurates - analysis; histidyl-leucine; Hydrogen-Ion Concentration; microextraction; o-phthalaldehyde; o-Phthalaldehyde - analysis; Oligopeptides - analysis; Peptidyl-Dipeptidase A - analysis; Rabbits; Reproducibility of Results; hippurate; histidyl-leucine; microextraction; angiotensin converting enzyme; o-phthalaldehyde; capillary electrophoresis
• ISSN: 0003-2697; 1096-0309
• DOI: 10.1006/abio.2001.5005

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 (λ 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.