Composition of Cytochrome c Oxidase 



289 



reported elsewhere. There were 13-9% (of the total lipid P) of inositol- 

 phosphatide and 5-9 % of sphingomyelin, both of which occur only in trace 

 amounts in the cytochrome 6 — q preparation. In addition to these differ- 

 ences, the oxidase alone contained an unidentified hpid which had the same 

 mobility as a long chain cholesterol ester, but which gave different colour 

 tests from those given by the ester. The oxidase contained a small amount of 

 a fraction which, after reduction, and passage through florisil, had peaks in 

 its absorption spectrum at 232 m/^ and 272 m/i. The latter peak probably 

 indicates the presence of the coenzyme Q of Crane, Hatefi, Lester and 

 Widmer (1957). 



Table 3. Reacttvation of cytochrome c oxidase 

 with a deoxycholate extract 



* 2% deoxycholate to the insoluble heart muscle mito- 

 chondrial fragments, followed by 4% cholate, and then 

 1-5% deoxycholate. 



Table 4. REACTrvATioN of cytochrome c oxidase 

 (Preparation 2-4-1-5*) with Phosphatides 



* 2% deoxycholate to the insoluble heart muscle 

 mitochondrial fragments, followed by 4% cholate, 

 and then 2 % deoxycholate. 



t 0-012 mg phosphatide P per cuvette, except 

 crude phosphatidylcholine of which 0-25 mg was 

 added. 



