226 BIOCHEMISTRY OF BACTERIAL LUMINESCENCE 



tion of factors which, on the basis of the effect of the aldehydes on 

 respiratory activity or other work with nonluminous organisms, might 

 be expected to react with each other, resulted in rise times of very 

 similar or identical magnitudes (Strehler and Cormier, 1954a). For 

 example, if malic acid were used as a hydrogen doner to reduce DPN 

 and the time course of the luminescence was plotted according to the 

 equation log (R max. — R obs.)/time = —a, the slope of the line ob- 

 tained was the same whether malate or DPN was the last added com- 

 ponent. Similarly, oxidized flavin or reduced DPN when added last 

 exhibited similar rise times, and reduced flavin, oxygen, or aldehyde 

 produced increases in luminescence, whose rate of approach to steady 

 state conditions were comparatively close to each other. These results 

 are summarized in Table III. 



TABLE III 



Time Required for Half-Maximal Luminescence in Bacterial Extracts 

 When Various Essential Components Are Added Last 



In any system consisting of a number of consecutive steps, it might 

 be expected that the steps further separated from the final reaction 

 would require longer to reach steady-state rates than those separated 

 by one or a few steps. This expectation is borne out in the data pre- 

 sented in Fig. 11. 



Studies with Reduced Flavins 



In cooperation with Dr. Harvey and Mr. Chang of Princeton Uni- 

 versity a number of experiments were performed to test the hypothe- 

 sis that the sole function of DPNHo was to reduce FMN. It was 



