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Angiotensin‐converting enzyme associated with Torpedo californica electric organ membranes
Author(s) -
Altstein M.,
Dudai Y.,
Vogel Z.
Publication year - 1987
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490180210
Subject(s) - phosphoramidon , torpedo , chemistry , membrane , thiorphan , enkephalin , enzyme , electric organ , neprilysin , liposome , angiotensin converting enzyme , peptide , biochemistry , chromatography , endocrinology , biology , receptor , acetylcholine receptor , opioid , blood pressure
Torpedo electric organ contains high concentrations of angiotensin converting enzyme (ACE) like activity, cleaving [Leu 5 ]enkephalin at the Gly 3 ‐Phe 4 peptide bond. Most of the activity cosediments with the cell membranes. The enzymatic preparation from membranes is inhibited by low concentrations of the ACE inhibitors, AQ 14225 and SQ 20881 (IC 50 of 0.6 and 15 nM, respectively), and is weakly inhibited by the neutral endopeptidase inhibitors, phosphoramidon and thiorphan (IC 50 of 30 μM and ca. 70 nM, respectively). The enzyme degrades hippuryl‐His‐Leu and is activated by NaCl. Hippuryl‐His‐Leu and [Leu 5 ]enkephalin are degraded with Km of 93 and 41 μM, and V max of 21 and 10 nmol/mg protein/min, respectively. The specific activity of the ACE‐like activity in homogenates of Torpedo electric organ is relatively high (6.3 nmol hippuryl‐His‐Leu/mg protein/min); this value is similar to that obtained for rat lung and rat striatum.