and (b)). A variety of different instruments and media have been pro- 

 posed for the preparation of homogenates and the suspension of cells 

 during the isolation process. Critical evaluations of the various methods 

 used to isolate cell components may be found in a number of extensive 

 reviews. 



Figure 11-37. Separation of Cell Components in Rat Liver Homogenate 

 (H) by Continuous Sucrose Gradient: (a) before centrif Ligation; (b) after 

 centrifugation. (From Anderson. N. G., 1956. "Techniques for the Mass 

 Isolation of Cellular Components," /// Oster, G. and Pollister, A. W. (Eds.), 

 "Physical Techniques in Biological Research," 3, Academic Press, New 

 York, N. Y., Fig. 16, p. 338. Courtesy of Dr. Norman G. Anderson, Oak 

 Ridge National Laboratory.) 



■ To avoid the loss of nucleoproteins and enzymes from cell structures, 

 particularly nuclei, during the isolation procedure, the method of Behrens 

 has proved useful. In this method, tissues are frozen-dried, suspended 

 in a nonaqueous solvent, and then homogenized by forcing through a 



260 / CHAPTER 11 



