EFFECT OF INHIBITORS ON THE TRANSPORT OF DINITROPHENYL-S-GLUTATHIONE IN HUMAN ERYTHROCYTES

Effect of inhibitors on and pH dependence of the export of dinitrophen yl-S-glutathione (DNP-SG), a glutathione S-conjugate formed upon in vi vo conjugation of 1-chloro-2,4-dinitrobenzene to glutathione, was stud ied in intact human erythrocytes. The transport was inhibited by ortho vanadate (IC50 = 80 mu M) and fluoride (IC50 = 9 mM) ions, by N-ethylm aleimide (IC50 = 200 mu M) and by intracellular calcium ions (IC50 = 7 00 nM). Erythrocyte anion exchange (Band 3) protein inhibitors DIDS an d SITS did not exert any significant effect on the transport. The tran sport rate increased with increasing extracellular pH in the range of 6.0-8.0. The Arrhenius activation energy of the process was 72.4+/-1.3 kJ/mol. Membrane potential, extracellular sodium/potassium concentrat ion ratio and extracellular osmolality in the range 300-600 mOsm did n ot influence the export rate.