444 



R. W. ESTABROOK 



(1954b) has termed these type I and type II cytochrome c. One sees that the 

 first material to be eluted (Type la) has very well defined c^^- and c^^a-bands. 

 As subsequent samples are eluted, the degree of resolution of these two bands 

 gradually diminishes until we see in the last sample to be eluted from the 

 column (Type lie) that there is merely a small shoulder indicative of the 

 presence of r„2- Margoliash, Frohwirt and Wiener (1959) have characterized 

 this last fraction as a trichloroacetic acid (TCA)-denatured cytochrome c, 

 and have investigated in detail the chemical and enzymic activities of these 

 fractions, showing that the TCA-modified cytochrome c has lost a large part 

 of its enzymic activity. Thus another means of modifying the split of the 

 absorption bands observed at low temperature is by acid denaturation of the 

 cytochrome c. 



Cytochrome cfrom Other Sources 



One further means of obtaining a difference in the fine band structure 

 of cytochrome c is to prepare the pigment from other sources. We have 



Fig. 8. A comparison of the spectral properties of reduced cytochrome c 

 prepared from heart muscle and from yeast. Samples of cytochrome c diluted in 

 0-1 M phosphate buffer, pH 7-4 were reduced with Na2S204 and diluted with an 

 equal volume of glycerol. Curve A represents the spectrum obtained with yeast 

 cytochrome c while Curve B is that obtained using heart muscle cytochrome c. 

 Optical depth equals 1 mm. Condition II. 



purified the pigments and investigated the spectra of cytochrome c from wheat 

 germ, flight muscle sarcosomes of the house fly, rat Hvers, and yeast. All 

 of the samples assayed, except that from yeast (Note 5), siiowed essentially 



