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METABOLISM AND PHYSIOLOGY 



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Minutes 



Fig. 5. Kinetics and Efficiency of Aerobic Phosphoryla- 

 tion— An incubation mixture (see experimental procedure) 

 was warmed for five minutes at 30°C (in the absence of 

 enzyme). An aliquot was withdrawn and acidified with 

 TCA (zero time), and the reaction was initiated by adding 

 enzyme (26 jug of a sucrose fraction in a final incubation 

 volume of 734 /il). Optical density at 340 m^ was followed 

 (30°C,thermostated cuvette compartment) and at intervals 

 aliquots were withdrawn and acidified with TCA. The su- 

 crose gradient fraction used contained maximal succinic 

 dehydrogenase activity (in a sucrose density gradient 

 centrifugation of crude dark extract). All values given have 

 been corrected for the zero time blank (0.25 m//moles/ 

 ml). A control tube, lacking DPNH, incubated at 30°C for 

 12 minutes gave a value of 0.98 m//moles M-6-P/ml. 



