NADH-ascorbate free radical and -ferricyanide reductase activities represent different levels of plasma membrane electron transport.
Plasma membranes isolated from rat liver by two-phase partition exhibited dehydrogenase activities for ascorbate free radical (AFR) and ferricyanide reduction in a ratio of specific activities of 1:40. NADH-AFR reductase could not be solubilized by detergents from plasma membrane fractions. NADH-AFR reductase was inhibited in both clathrin-depleted membrane and membranes incubated with anti-clathrin antiserum. This activity was reconstituted in plasma membranes in proportion to the amount of clathrin-enriched supernatant added. NADH ferricyanide reductase was unaffected by both clathrin-depletion and antibody incubation and was fully solubilized by detergents. Also, wheat germ agglutinin only inhibited NADH-AFR reductase. The findings suggest that NADH-AFR reductase and NADH-ferricyanide reductase activities of plasma membrane represent different levels of the electron transport chain. The inability of the NADH-AFR reductase to survive detergent solubilization might indicate the involvement of more than one protein in the electron transport from NADH to the AFR but not to ferricyanide.
Villalba
J M
JM
Departamento de Biología Celular, Facultad de Ciencias, Universidad de Córdoba, Spain.
Canalejo
A
A
Rodríguez-Aguilera
J C
JC
Burón
M I
MI
Mooré
D J
DJ
Navas
P
P
D000818:Animals; D002793:Cholic Acids; D003034:Coated Pits, Cell-Membrane / Q000201:enzymology; D004579:Electron Transport; D004591:Electrophoresis, Polyacrylamide Gel; D005609:Free Radicals; D008099:Liver / Q000201:enzymology / Q000648:ultrastructure; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism*; D009245:NADH Dehydrogenase / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D010084:Oxidation-Reduction; D051381:Rats; D017208:Rats, Wistar; D014909:Wheat Germ Agglutinins / Q000494:pharmacology
D002793:Cholic Acids; D005609:Free Radicals; D008565:Membrane Proteins; D014909:Wheat Germ Agglutinins; D009247:NADH, NADPH Oxidoreductases; C023927:monodehydroascorbate reductase (NADH); C014227:ferricyanide reductase; D009245:NADH Dehydrogenase; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate