Acein-1, a novel angiotensin-I-converting enzyme inhibitory peptide isolated from tryptic hydrolysate of human plasma

  • FEBS Lett. 1998 Nov 6;438(3):255-7. doi: 10.1016/s0014-5793(98)01311-8.
K Nakagomi  1 ,  A Fujimura ,  H Ebisu ,  T Sakai ,  Y Sadakane ,  N Fujii ,  T Tanimura
Affiliations
  • 1. Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, Japan. [email protected]
PMID: 9827556 DOI: 10.1016/s0014-5793(98)01311-8
Abstract

A novel angiotensin-I-converting enzyme (ACE) inhibitory peptide, designated acein-1, was isolated from the tryptic hydrolysate of human plasma. Gel filtration and cation exchange chromatography were performed to purify this peptide, followed by reversed-phase gradient and isocratic high-performance liquid chromatography. Acein-1 was found to be a heptapeptide, Tyr-Leu-Tyr-Glu-Ile-Ala-Arg, corresponding to f(138-144) of human serum albumin. The synthetic heptapeptide, hexapeptide (Tyr-Leu-Tyr-Glu-Ile-Ala, des-7R acein-1) and octapeptide (Tyr-Leu-Tyr-Glu-Ile-Ala-Arg-Arg, acein-1R) showed dose-dependent inhibitions of ACE, and their IC50 values were 16 micromol/l, 500 micromol/l and 86 micromol/l, respectively. Acein-1 might be a non-competitive inhibitor, while acein-1R may be an uncompetitive inhibitor, as shown by Lineweaver-Burk plots.

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