title: [Effect of 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, a ubiquinone analog, and SH-reagents on the electrogenic function of pyrophosphatase from Rhodospirillum rubrum chromatophores].
abstract: Inorganic pyrophosphate-induced membrane potential generation in Rhodospirillum rubrum chromatophores is inhibited by 2,5-dibromo-2-methyl-6-isopropyl-p-benzoquinone (DBMIB). The inhibition is increased by menadione and dithionite and is not relieved by ascorbate; this effect is probably due to a displacement of the intrachromatophore quinones by DBMIB. The SH-reagents, N-ethylmaleimide and p-chloromercurybenzoate at high concentrations inhibit membrane potential generation driven by inorganic pyrophosphate hydrolysis, thus suggesting the involvement of SH-groups in pyrophosphatase operation. The mechanism of regulation of the mode of action of pyrophosphatase by quinones and the location of the SH-groups of the enzyme are discussed.
mesh_terms: D020130:Bacterial Chromatophores / Q000201:enzymology*; D002729:Chloromercuribenzoates / Q000494:pharmacology; D003991:Dibromothymoquinone / Q000494:pharmacology*; D005033:Ethylmaleimide / Q000494:pharmacology; D043564:Inorganic Pyrophosphatase; D007700:Kinetics; D011755:Pyrophosphatases / Q000378:metabolism*; D011809:Quinones / Q000494:pharmacology*; D012247:Rhodospirillum rubrum / Q000201:enzymology*; D013439:Sulfhydryl Reagents / Q000494:pharmacology*; D020245:p-Chloromercuribenzoic Acid
chemical_list: D002729:Chloromercuribenzoates; D011809:Quinones; D013439:Sulfhydryl Reagents; D003991:Dibromothymoquinone; D020245:p-Chloromercuribenzoic Acid; D011755:Pyrophosphatases; D043564:Inorganic Pyrophosphatase; D005033:Ethylmaleimide
vernacular_title: Deĭstvie 2,5-dibrom-3-metil-6-izopropil-p-benzokhinona, analoga ubikhinona, i SH-reagentov na élektrogennuiu funktsiiu pirofosfatazy khromatoforov Rhodospirillum rubrum.