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2,5‐Di( tert ‐butyl)‐1,4‐benzohydroquinone — a novel inhibitor of liver microsomal Ca 2+ sequestration
Author(s) -
Moore Gregory A.,
McConkey David J.,
Kass Georges E.N.,
O'Brien Peter J.,
Orrenius Sten
Publication year - 1987
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(87)80479-9
Subject(s) - microsome , chemistry , atpase , microsoma , biochemistry , mitochondrion , enzyme , endoplasmic reticulum , membrane permeability , membrane
Treatment of rat liver microsomes with 2,5‐di( tert ‐butyl)‐1,4‐benzohydroquinone caused a dose‐related inhibition ( K i ⋍1 μM) of ATP‐dependent Ca 2+ sequestration. This was paralleled by a similar impairment of the microsomal Ca 2+ ‐stimulated ATPase activity. In contrast, the hydroquinone failed to induce Ca 2+ release from Ca 2+ ‐loaded liver mitochondria (supplied with ATP), and inhibited neither the mitochondrial F 1 F 0 ‐ATPase nor the Ca 2+ ‐stimulated ATPase activity of the hepatic plasma membrane fraction. The inhibition of microsomal Ca 2+ sequestration was not associated with any apparent alteration of membrane permeability or loss of other microsomal enzyme activities or modification of microsomal protein thiols. These findings suggest that 2,5‐di( tert ‐butyl)‐1,4‐benzohydroquinone is a potent and selective inhibitor of liver microsomal Ca 2+ sequestration which may be a useful tool in studies of Ca 2+ fluxes in intact cells and tissues.