Cell Structure and Metabolic Regulation 27 



ing in sucrose alone, or more so in sucrose-DOC solution (Table 

 II). This latter activated suspension, if let stand or if diluted 

 with sucrose, lost enzymic activity rapidly, and it was from 



Table II 



Effects of various treatments on DPNH-cytochrome c reductase 

 AND TPNH-cytochrome c reductase activities of 



RAT LIVER microsomes 



The undiluted microsome suspension contained microsomes from 214 mg. 

 wet weight liver in Expt. 8 and 200 mg. wet weight liver in Expt. 13. All 

 centrifugations were performed at 105,000 g. DOC = deoxycholate, pH 

 7-5-7-8. 



[imoles PNH 

 oxid.jmin.jg. liver 



Expt. No. 

 8 



13 



Treatment 



In sucrose, fresh 



In sucrose, kept 6 hr. at 0°C 



In 0-26% DOC, fresh 



In • 26 % DOC, kept 3 hr. at 



0°C 

 In • 26 % DOC, kept 6 hr. at 



0°C 

 In • 26 % DOC, then diluted 



2-5 x,kept 6hr. at 0°C 

 In • 26 % DOC, then diluted 



5 X , kept 6 hr. at 0°C 

 In -26 % DOC, then diluted 



10 X , kept 6 hr. at 0°C 

 In 026% DOC, kept 6 hr. 



atO°C 



In sucrose, fresh 



In sucrose, kept 8 hr. at 0°C 



Treated with 0-26% DOC, 

 then centrifuged 2 hr. 



Supernatant from above, dilu- 

 ted 5 x , kept 6 hr. at 0°C 



Above, centrifuged 6 hr. 



Above, centrifuged 6 hr. Supernatant from 



above 



2-7 0-58 



Data taken from Ernster, Palade and Siekevitz (unpublished). 



this suspension that we obtained our microsomal membrane 

 fraction. Because of these responses, dependent on the chosen 

 base-line, on the activity of the original microsomes, or upon 

 that of the activated microsomes, or upon that of the diluted 

 low-activity microsomes, we obtained a wide range of recovery 



