A fluorometric assay for angiotensin-converting enzyme activity

Michael S. Kapiloff, Stephen M. Strittmatter, Lloyd D. Fricker, Solomon H. Snyder

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

A simple and sensitive assay for angiotensin-converting enzyme (ACE; EC 3.4.15.1) activity has been developed which employs fluorescently labeled tripeptides. ACE hydrolyzes dansyl-phenylalanyl-arginyl-tryptophan or dansyl-phenylalanyl-arginyl-phenylalanine, liberating dansyl-phenylalanine and a dipeptide. Dansyl-phenylalanine partitions quantitatively into chloroform, whereas the substrates are virtually insoluble in chloroform. This allows rapid measurement of ACE activity with high signal-to-noise ratios even when microliter aliquots of human serum are assayed. Inhibition studies of the dansyl-tripeptide cleaving activity of human serum and rat lung, the identity of the products of enzyme action, and the regional distribution of enzyme activity among rat tissues demonstrate that only ACE cleaves these substrates under the conditions employed here. This assay may be useful for the clinical measurement of human serum ACE activity and for research investigations of ACE from a variety of tissues.

Original languageEnglish (US)
Pages (from-to)293-302
Number of pages10
JournalAnalytical Biochemistry
Volume140
Issue number1
DOIs
StatePublished - Jul 1984

Keywords

  • dansyl-tripeptides
  • fluorometric enzyme assay
  • hippuryl-histidylleucine
  • sarcoidosis

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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