250 



LIGHT AND LIFE 



limiting lactor lor light emission. Simultaneous studies by McElroy, 

 Hastings and associates demonstrated that FMN and an additional 

 factor, subsequently identified by Strehler and Cormier as a long- 

 chain aldehyde, were required for light emission (17, 18) . These and 

 other observations indicated that the following over-all reaction was 

 the basic one concerned with light emission: 



FMNH. + R~C 



^ 



O 



+ 0.2 + ^ 



light 



H 



Studies by Cormier and Totter (5) and by McElroy and Green 



(13) indicated that at least two enzymes were required to obtain 



light emission from DPNH. By dialysis at low pW Cormier et al. 



0.5 10 15 2 2 5 3.0 



CONC. REDUCED FMN-MxIO^ 



35 



Mg. L'H. Rclatioii,shi|) hctwcni liglit inlc-iisity and reduced !"M\. Initial li'.;lil 

 iiUensily, in arbitrary unils, ol a eoiistant bacterial extract solution as a function 

 of the amount of reduced I'MX injected into ihe sohition. The closed circles 

 lepresent a duplicate run starling with a higher en/ynic concentration. In the 

 upper right portion of the figure is a Miciiaelis-Mentcn plot of tlie data, inditat 

 ing a two site en/vniatic oxidation of IMNH.. 



