CYTOCHEMICAL-LOCALIZATION OF NADH-FERRICYANIDE OXIDOREDUCTASE IN HYPOCOTYL SEGMENTS AND ISOLATED MEMBRANE-VESICLES OF SOYBEAN

NADH-ferricyanide oxido-reductase activity was demonstrated at the inner (cytoplasmic) aspect of plasma membranes and plasma membrane vesicles from hypocotyles of etiolated soybean (Glycine max L.) seedings by cytochemical procedures. The plasma membrane-associated activity, observed in both tissue and vesicle preparations, resisted fixation in 0.1% glutaraldehyde, required the presence of exogenous pyridine nucleotide and was inhibited by adriamycin. With tissue, the activity could be demonstrated only with broken cells where reactants could penetrate freely. With vesicles of plasma membrane origin, activity was seem only with cytoplasmic side out vesicles (fraction E) prepared by free-flow electrophoresis. Activity was observed also on the cytoplasmic surface of the tonoplast and on putative tonoplast vesicles oriented cytoplasmic side out.