An NADH-dependent disulfide reductase activity in the endoplasmic reticulum of Dictyostelium discoideum.
A novel disulfide reductase activity was observed in the amoeba, Dictyostelium discoideum. Both 5,5'-dithiobis(2-nitro-benzoate) (DTNB) and insulin were substrates for reduction. NADH was utilized in preference to NADPH. The activity comigrated with NADPH-dependent cytochrome c reductase on sucrose gradients, suggesting localization in the endoplasmic reticulum (ER). The buoyant density of the disulfide reductase was not shifted when ribosomes were released from the ER nor was the activity solubilized when membranes were shocked with low osmotic buffer. It therefore appears that the reductase was membrane-bound in the lumen of the smooth ER.
Sarkar
S
S
Department of Biochemistry and Molecular Biology, University of Chicago, Illinois 60637, USA.
Steck
T L
TL
D000818:Animals; D004023:Dictyostelium / Q000201:enzymology*; D004228:Dithionitrobenzoic Acid; D018871:Endoplasmic Reticulum, Smooth / Q000201:enzymology; D007328:Insulin; D009247:NADH, NADPH Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D013347:Subcellular Fractions / Q000201:enzymology; D013379:Substrate Specificity
D007328:Insulin; D004228:Dithionitrobenzoic Acid; D009247:NADH, NADPH Oxidoreductases; C014703:disulfide reductase (NADH)