ISSN:
0730-2312
Keywords:
S-transferase
;
heme transport
;
erythroleukemic cells
;
inhibited glutathione conjugation
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
The possibility that glutathione-S-transferases can serve as heme carriers in cells was studied via the following two characteristics: the ability to bind hemin reversibly and the coordination between heme and glutahione-S-transferases level in the cell. Two erythroleukemic cell lines that can be induced to synthesize hemoglobin were studied, K-562 and Friend murine erythroleukemia cells. It was found that hemin-associated glutathione-S-transferase tends to lose its native structure as expressed by partial irreversible inhibition of glutathione conjugation activity. In K-562 cells, a small increase in heme synthesis was induced, but under no condition could glutathione-S-transferase be elevated. In addition, introduction of high hemin from without caused large hemoglobin production but did not inducechanges in the glutathione-S-transferase content. Dimethyl sulfoxide-induced Friend murine eryth-roleukemia cells synthesized a large amount of endogenous hemin that had to be transported from the mitochondria for hemoglobin synthesis. Although a concomitant increase in glutathione-S-transferase level (20-40%) was observed, it was only short-lived, unlike hemin, which continued to increase. These data indicate a lack of correlation between glutathione-S-transferase and hemin or hemoglobin levels. Finally, dimethyl sulfoxide-induced cells were treated with succinyl acetone to inhibit heme synthesis. These cells showed the same increased levels and time-dependent pattern of gluathione-S-transferase as untreated cells. A similar phenomenon was observed when different substrates were used to measure the activities of glutathione-S-transferases. These results raise doubts about the possibility of glutathione-S-transferases functioning as heme carriers in cells.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcb.240410302
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