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The bradykininase activities of extracts of dog lung
Author(s) -
ALABASTER VALERIE A.,
BAKHLE Y. S.
Publication year - 1973
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1973.tb08207.x
Subject(s) - chemistry , bradykinin , chloride , enzyme , biochemistry , venom , hydrolysis , angiotensin ii , chromatography , organic chemistry , receptor
Summary1 Homogenates of dog lungs freed from blood inactivate bradykinin. The bradykininase activity is present in soluble and particulate subcellular fractions. 2 The fraction with the highest relative specific activity is that sedimenting between 8,700 g and 78,000 g. This fraction has been studied in more detail. 3 There is evidence for two bradykinin inactivating enzymes in this fraction with apparent K m values of 7·5 μ m and 120 μ m . 4 The bradykininase activity is not dependent on the concentration of chloride ion. 5 The bradykininase activity is inhibited by EDTA, 2:3‐dimercaptopropanol, nickel ions and some of the peptides from the venom of Bothrops jararaca and of Agkistrodon halys blomhoffii but not by 2‐mercaptoethanol or N‐ethylmaleimide. 6 Angiotensin II in either 15 or 170 m m chloride ion is not an inhibitor of bradykininase activity but angiotensin I at either chloride concentration is an inhibitor. It is proposed that chloride is not necessary for binding of angiotensin I to converting enzyme but is necessary to ensure the correct orientation of substrate for hydrolysis to proceed.