Isolation and Characterization of the N-domain of Bovine Angiotensin-Converting Enzyme

P. V. Binevski¹, I. I. Nikolskaya¹, V. F. Pozdnev², and O. A. Kost^1*

¹School of Chemistry, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (095) 939-5417; E-mail: kost@enzyme.chem.msu.ru

²Institute of Biomedical Chemistry, Russian Academy of Medical Sciences, ul. Pogodinskaya 10, Moscow, 119832 Russia; fax: (095) 245-0857; E-mail: inst@ibmh.msk.su

^* To whom correspondence should be addressed.

Received December 1, 1999; Revision received January 12, 2000

---

A method for preparation of a catalytically active fragment of bovine lung angiotensin-converting enzyme (ACE) has been developed. It includes limited proteolysis of the full-length somatic form of the enzyme by trypsin. The resulting fragment corresponds to the N-terminal domain of angiotensin-converting enzyme. The influence of chloride and sulfate anions on the enzymatic activity of this fragment has been investigated, and kinetic parameters for hydrolysis of synthetic tripeptide substrates catalyzed by the N-domain of ACE have been determined. Comparison of these parameters with those obtained for full-length somatic bovine ACE suggests that in the bovine somatic ACE molecule active centers located in various domains may function interdependently.

---

KEY WORDS: angiotensin-converting enzyme, N-terminal domain, kinetic parameters

---