The effect of sulfhydryl blocking agents on the uptake of L-carnitine in an established human cell line (CCL 27).
The effect of sulfhydryl blocking agents on the active transport of L-carnitine into cells from an established cell line from human heart was studied. N-ethylmaleimide (MalNEt), 5,5-dithiobis-(2-nitrobenzoic acid) (Nbs2), parachloromercuribenzoate (ClHgBzO-) and cystamin all reduced the uptake of L-carnitine considerably. This was not due to a general membrane injury as judged by the trypan blue dye exclusion test. The inhibition caused by N-ethylmaleimide was irreversible, while that of Nbs2, ClHgBzO- and cystamin could be reversed by dithiothreitol. Excess L-carnitine in the medium exerted a small protective effect against the inhibition of Nbs2, but had no effect against the inhibition of the other agents. Neither could ClHgBzO- protect the uptake mechanism against the irreversible inhibition of N-ethylmaleimide. We conclude that the observations reflect the existence of a multitude of different SH-groups, and that some of these are essential for the cellular uptake of L-carnitine.
D001693:Biological Transport, Active; D002331:Carnitine / Q000378:metabolism*; D002460:Cell Line; D002729:Chloromercuribenzoates / Q000494:pharmacology; D003538:Cystamine / Q000494:pharmacology; D004228:Dithionitrobenzoic Acid / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D006801:Humans; D009206:Myocardium / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000494:pharmacology*; D020245:p-Chloromercuribenzoic Acid
D002729:Chloromercuribenzoates; D013438:Sulfhydryl Compounds; D020245:p-Chloromercuribenzoic Acid; D004228:Dithionitrobenzoic Acid; D005033:Ethylmaleimide; D003538:Cystamine; D002331:Carnitine; D004229:Dithiothreitol