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Properties of partially purified liver microsomal cytochrome P ‐450: Acceptance of two electrons during anaerobic titration
Author(s) -
Ballou David P.,
Veeger Cornelis,
van der Hoeven Theodore A.,
Coon Minor J.
Publication year - 1974
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(74)80086-4
Subject(s) - medical school , library science , chemistry , medicine , medical education , computer science
A large variety of foreign compounds, including drugs, petroleum products and insecticides, as well as physiological substrates such as fatty acids and steroids, are attacked by molecular oxygen in the presence of NADPH, a reductase and liver microsomal cytochrome P-450 (P-450LM) as the oxygenating catalyst. Although much has been learned about the hydroxylation reactions catalyzed by liver microsomes, characterization of the components of the enzyme system and elucidation of the reaction mechanism have been hampered by the instability ofP-450LM, which forms an altered, inactive hemoprotein (P-420) when removed from the membrane [ 1]. Several years ago, this laboratory [2, 3] reported the resolution of this enzyme system from rabbit and rat liver microsomes into three components which, when combined, reconstituted hydroxylation activity toward drugs, fatty acids and hydrocarbons [4-7]. These components were identified as a solubilized form of cytochrome P-450, a solubilized form of NADPH-cytochrome P-450 reductase, and phosphatidylcholine. The present paper provides that partially purified P-450LM [8, 9] accepts two electrons from dithionite