Tiie Carbon Nio~oxide Comi~oukds of the Cytoctiropie Oxtdases

In previous papers we have described methods for accurately measuring the spectra that represent the differences between the oxidized and the reduced forms of the cytochrome components of the turbid heart muscle particles that contain the intact succinic oxidase system (1, 2). In order to extend the pioneer observations of Keilin and Hartree on the carbon monoxide compound of cytochrome a3 (3) and in order to delineate the oxidase components of various cells in more detail, we present for the first time direct recordings of the spectra that represent the differences between the carbon monoxide compounds of the cytochromes and their reduced forms in highly active heart muscle prcparat,ions, bakers yeast cells, Bacillus subtiliis, Acetobacter pasteurianum, Xtaphylococcus albus, and Aerobacter aerogenes, etc. A comparison of t’he Soret bands of the carbon monoxide compounds verifies that Keilin and Hartree’s cytochromc a3 of heart muscle is very similar to the cytochromc oxidase of bakers’ yeast and B. subtilis. On the other hand, the Soret band of the carbon monoxide compound of the cytochrome oxidaser of A. pasteurianum differs significantly from that, of yeast and muscle and the spectrum of a new CO-binding pigmcnP of S. albus differs markedly from any ot)hcr known cytochrome (3, 4). And A. awogenes shows a scarcely detectable amount of any CO-binding pigment in the region of the Soret band. On the basis of studies of a variety of bacteria, various patterns of their CO-binding cytochromes are delineated. ‘These data are corrclnted with the spectra of reduced cyt80chromes in a paper to be published by Dr. Lucile Smith.