期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1980
卷号：77
期号：11
页码：6359-6362
DOI：10.1073/pnas.77.11.6359
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Purified inside-out vesicles from human erythrocytes were used to investigate the active transport of oxidized glutathione (GSSG). Incubation of vesicles and GSSG in the presence of ATP resulted in the transport of GSSG into the vesicles. When vesicles were incubated with reduced glutathione (GSH), no transport was observed. At GSSG concentrations of less than 5 mM, transport was linear up to 4 hr at 37 degrees C. A Lineweaver-Burk plot of the transport rate as a function of GSSG concentration was biphasic and gave apparent Km values of 0.1 and 7.1 mM. The Km for ATP . Mg in this transport process was 0.63 mM at a GSSG concentration of 20 microM and 1.25 mM at a GSSG concentration of 5 mM. The transport rate at low GSSG concentrations was inhibited by CTP or UTP, which acted as competitive inhibitors of ATP; Ki=0.51 mM. This inhibition may account for the high erythrocyte GSH levels observed in pyrimidine-5'-nucleotidase deficiency, a disorder in which erythrocytic levels of CTP and UTP are elevated.
