1 82 E. R. REDFEARN 



of fractions showed weak absorption at various wavelengths between 230 

 and 300 m/i. There was, however, no evidence of spectra characteristic of 

 the tocopherols or the vitamins K. 



Extraction of lipids with organic solvents 



An obvious way to tackle the problem of lipid function in mitochondrial 

 particles is to remove the lipid by a suitable extraction procedure and 

 observe the effect on enzyme activities. Nason and Lehman [2, 3] did this 



TABLE II 



Effect of Number of E^xtractions with Light Petroleum on the Succinic 

 Oxidase and Cytochrome Oxidase Activities of Pig Heart- 

 Muscle Preparation 



Expt. No. I : 2 ml. preparation (age 3 days) extracted successively with 4 ml. 



40-60 light petroleum for i min. 

 Expt. No. 2 : I ml. preparation (age 7 days) extracted successively with i ml. 



40-60 light petroleum for i min. 

 Expt. No. 3 : I ml. preparation (age i day) extracted successively with 5 ml. 



40-60 light petroleum for i -5 min. 

 Enzyme activities determined as described by Redfearn et al. [11]. 



simply by shaking the enzyme preparation with an organic solvent such 

 as isooctane. After such a treatment it was found that the succinic- and 

 DPNH-cytochrome c reductase activities had fallen considerably but 

 that they could be restored to their original levels by adding a-tocopherol 

 as a suspension in bovine serum albumin. Although it was later shown [4] 

 that other substances would also reactivate solvent-extracted preparations 

 a hypothesis was put forward implicating y.-tocopherol as an essential 

 component of the electron transport system [5]. The specificity of 

 the reactivation by tocopherol was doubted by Deul et al. [6]. Redfearn 

 and Pumphrey [7] then showed that the loss of enzymic activity after 



