ATP-dependent S-(2,4-dinitrophenyl)glutathione transport in canalicular plasma membrane vesicles from rat liver.

摘要: Uptake of the thioether S-(2,4-dinitrophenyl)glutathione (DNPSG) in canalicular plasma membrane vesicles from rat liver is enhanced presence ATP and exhibits an overshoot with a transient 5.5-fold accumulation DNPSG. Stimulation by not caused generation potential, based on responses indicator dye oxonol V. ATP-dependent uptake has apparent Km 71 microM for DNPSG Vmax 0.34 nmol.min-1.mg vesicle protein-1. Protein thiol groups are essential transport activity as indicated sensitivity to sulfhydryl reagents. There competitive inhibition other thioethers, S-hexylglutathione (Ki = 66 microM), photoaffinity label S-(4-azidophenacyl)glutathione 56 well glutathione disulfide 0.44 mM) bile acid taurocholate 0.61 mM). GSH (2 or cholate (0.4 does inhibit. Both show which inhibited No found GSH. Transport also competitively alpha-naphthyl-beta-D-glucuronide 0.42 but alpha-naphthylsulfate mM), there substantial glucuronides ebselen p-nitrophenol. The results indicate that system directly driven biliary classes compounds may proceed via this system.