ISSN:
1573-6881
Keywords:
Transmembranous NADH-dehydrogenase
;
enzyme kinetics
;
human erythrocyte
;
plasma membrane
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Physics
Notes:
Abstract Evidence is presented for a transmembranous NADH-dehydrogenase in human erythrocyte plasma membrane. We suggest that this enzyme is responsible for the ferricyanide reduction by intact cells. This NADH-dehydrogenase is distinctly different from the NADH-cytochromeb 5 reductase on the cytoplasmic side of the membrane. Pretreatment of erythrocytes with the nonpenetrating inhibitor diazobenzene sulfonate (DABS) results in a 35% loss of NADH-ferricyanide reductase activity in the isolated plasma membrane. Since NADH and ferricyanide are both impermeable, the transmembrane enzyme can only be assayed in open membrane sheets with both surfaces exposed, and not in closed vesicles. The transmembrane dehydrogenase has affinity constants of 90 µM for NADH and 125 µM for ferricyanide. It is inhibited byp-chloromercuribenzoate, bathophenanthroline sulfonate, and chlorpromazine.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00743243
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