Abstract
Dinitrophenyl S-glutathione is accumulated by inside-out vesicles made from human erythrocytes in a process totally dependent on ATP and Mg2+. The vesicles were shown to accumulate dinitrophenyl S-glutathione against a concentration gradient. The vesicles were able to concentrate this glutathione derivative even in the absence of membrane potential. This indicated that the ATP-dependent uptake of dinitrophenyl S-glutathione by inside-out vesicles represented an active transport process. Neither extravesicular EGTA nor intravesicular ouabain inhibited the transport process, indicating that neither the Ca2+-ATPase nor the Na+, K+-ATPase were involved. These results indicated that dinitrophenyl S-glutathione uptake by inside-out vesicles probably represented primary active transport. The uptake of dinitrophenyl S-glutathione was a linear function of time (up to 5 h) and vesicle protein. The rate of uptake was optimal between pH 7.0 and 8.0 and at 37 degrees C. The Km values determined for dinitrophenyl S-glutathione and ATP were 0.29 mM and 1 mM, respectively. The transport process was completely inhibited by vanadate and by p-hydroxymercuribenzene sulphonate and inhibited to a lesser extent by N-ethylmaleimide. GTP could efficiently substitute for ATP as an energy source for the transport process, but CTP and UTP were comparatively much less effective.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.