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The effect of substrates and inhibitors of cytochrome P‐450 on the NADPH inhibition of the ATP‐dependent, hepatic, microsomal calcium pump
Author(s) -
Chen NengQian,
Holtzman Jordan L.
Publication year - 1990
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(90)80526-o
Subject(s) - cytochrome , isozyme , benzphetamine , microsome , chemistry , biochemistry , enzyme , cytochrome p450 , glutathione
In hepatic microsomes one or more isozymes of cytochrome P‐450 inhibits the ATP‐dependent Ca 2+ pump. This inhibition is reversible by GSH and appears to be due to a direct oxidation of the pump proteins by the oxygenated cytochrome. To determine which isozyme mediates this inhibiton, we have examined the effect of various substrates and inhibitors on the NADPH inhibition of Ca 2+ uptake. We find that aminopyrine, benzphetamine and SKF‐525A reverse this inhibition while a number of other substrates do not. This pattern suggests that a previously unreported isozyme of cytochrome P‐450 mediates the Ca 2+ pump inhibition.