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Differential sensitivity of membrane‐associated pyrophosphatases to inhibition by diphosphonates and fluoride delineates two classes of enzyme
Author(s) -
Baykov Alexander A.,
Dubnova Elena B.,
Bakuleva Natalia P.,
Evtushenko Olga A.,
Zhen Rui-Guang,
Rea Philip A.
Publication year - 1993
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(93)80169-u
Subject(s) - pyrophosphatases , pyrophosphatase , inorganic pyrophosphatase , pyrophosphate , rhodospirillum rubrum , biochemistry , enzyme , chemistry , membrane , vesicle , biology
1,1‐Diphosphonate analogs of pyrophosphate, containing an amino or a hydroxyl group on the bridge carbon atom, are potent inhibitors of the H + ‐translocating pyrophosphatases of chromatophores prepared from the bacterium Rhodospirillum rubrum and vacuolar membrane vesicles prepared from the plant Vigna radiata . The inhibition constant for aminomethylenediphosphonate, which binds competitively with respect to substrate, is below 2 μM. Rat liver mitochondrial pyrophosphatase is two orders of magnitude less sensitive to this compound but extremely sensitive to imidodiphosphate. By contrast, fluoride is highly effective only against the mitochondrial pyrophosphatase. It is concluded that the mitochondrial pyrophosphatase and the H + ‐pyrophosphatases of chromatophores and vacuolar membranes belong to two different classes of enzyme.