No enzymatic activities are necessary for the stabilization of ascorbic acid by K-562 cells.
We disprove that living cells stabilize ascorbate by the activity of a trans plasma membrane semidehydroascorbate reductase. The two processes show different specificities for both substrate and inhibitor. Not only cells but also cell-conditioned buffers stabilize ascorbate as long as compounds with molecular weights above 10 kDa are not removed. The effect is most probably due to chelation of traces of transition metals.
Schweinzer
E
E
Department of Medical Chemistry, University of Vienna, Wien, Austria.
Waeg
G
G
Esterbauer
H
H
Goldenberg
H
H
D001205:Ascorbic Acid / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology*; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013379:Substrate Specificity
D009247:NADH, NADPH Oxidoreductases; C023927:monodehydroascorbate reductase (NADH); D001205:Ascorbic Acid