The Estimation of Cytochrome C Oxidase in Animal Tissues

Abstract

Method for the stimation of cytochrom, c oxidase are dependent eitherupon the change which occurs in the absorption spectrum of cytochrome c whenit is oxidized by cytochrome oxidase (Altschul, Abrams, and Hogness 1939;Albaum, Tepperman and Bodansky 1946a, 1946b), or upon the absorption ofgaseous oxyen by, a !!ysten. which consists essentially of a preparation of cytochromeoX~,«Jase in the. pz:esence of a large excess of reduced cytochrome c. Ineither case, it is the rate of oxidation of reduced cytochrome c which is es~imated;in the former by spectrophotometric measurement of the rate of change in lighttransmission . at two different wllyelengths; and, in the latter by manometricestimation of the rate of oxygen uptake (Keilin and Hartree 1938; Stotz 1939;Schneider and Potter 1943). The rate of oxidation of the reduced cytochrome c . , ,"is proportional, under. certain, conditions, to the amount of cytochrome oxidasepresent, apd so. can be used as a measure of ~he activity' of cytochrome oxidase .itself.