Activity of the cytochrome system in heart muscle preparations

Abstract

The heart muscle prepn. for cytochrome oxidase of Keilin and Hartree (I) (Proc. Roy. Soc. B) was compared with the prepn. of Haas (II) (Jour. Biol. Chem.). I was a colloidal suspension free from Hb and contained a complete cytochrome system, succinic dehydrogenase and other enzymes, with a Qo2 of 1,400 at 39[degree] in the presence of excess cytochrome c and p-phenylenediamine. II was less active, contained Hb derivatives and had a pH > 9. Haas'' claim of 2 components of cytochrome oxidase was not confirmed. Enzyme II could be replaced by plasma proteins or denatured glo-bin.