Cytochemical demonstration of glutaraldehyde-resistant NADH-ferricyanide oxido-reductase activities in rat-liver plasma membranes and Golgi apparatus.

NADH-ferricyanide reductase activity was demonstrated in rat liver endomembranes by cytochemical procedures. The activity observed in plasma membrane and mature portions of the Golgi apparatus resisted fixation in 0.1% glutaraldehyde, a characteristic which permitted differentiation of the NADH-ferricyanide reductase of plasma membranes and mature Golgi apparatus elements from those of mitochondria, microbodies, endoplasmic reticulum and nuclear envelope. With the latter membranes, activity could be demonstrated only with unfixed material or following brief glutaraldehyde fixation and was greatest with broken cells or isolated fractions due to problems of penetration of reagents. Biochemical studies paralleled cytochemical findings with respect to glutaraldehyde fixation and sensitivity to other metabolic inhibitors. The findings provide evidence that a NADH-ferricyanide reductase may be among the membrane constituents conserved and/or modified during flow differentiation of membranes. The basis for a method to evaluate plasma membrane contamination of endoplasmic reticulum fractions and to differentiate among mature and immature secretory vesicles of the Golgi apparatus is also indicated.