70 E. C. Slater and W. C. Hulsmann 



Table III 



Extraction of uncoupling lipid from fresh and aged 

 cytochrome preparations 



Cytochrome preparations were extracted with tsooctane, after storage for 

 various times at 4°. After evaporation of the isooctane, the residue was dis- 

 solved in alcohol and a small sample of the alcoholic solution added to a 

 reaction system measuring the ^zp-ATP exchange reaction in freshly prepared 

 rat liver mitochondria. 



Thus, it appears that mitochrome is a haemprotein (or a 

 mixture of haemproteins) derived from the cytochromes. 

 There is a time correlation between the inactivation of the 

 cytochrome c oxidase (in the case of the cytochrome (a + Og) 

 preparation), the disappearance of the cytochrome spectrum, 

 the appearance of that of mitochrome and the extractabihty 

 of the uncoupHng substance by isooctane. This suggests the 

 following transformation 



cytochrome -> mitochrome + lipid 



J. 



lipid 



The lipid is normally bound to cytochrome, and is liberated 

 (and therefore becomes extract able by isooctane) during the 

 transformation of cytochrome to mitochrome. It must be 

 emphasized, however, that the possibility cannot be excluded 

 that the appearance of extractable lipid and the transforma- 

 tion of cytochrome to mitochrome are two unrelated processes 

 which take place during treatment of cytochrome preparations 

 with hydrolytic enzymes. 



Like that of the unextracted mitochrome preparation of 

 Polls and Shmukler, the uncoupling activity of the lipid 

 extracted by isooctane is counteracted by the addition of 

 albumin. It appears that albumin firmly binds the substance. 



