11. I). MrELlWY AND H. H. SELIGER 



251 



(f)) were able to inactivate the light-emitting system which depended 

 on DPNH. The system was able to emit light, however, in the 

 presence of retlnced FMN. Sulxseqnently Green and McElroy were 

 able to separate by calcium phosphate gel columns the DPNH-FMN 

 oxidase system from the luciferase preparation. Ammonium sulfate 

 fractionation of this preparation yields an active enzyme which is 

 homogeneous in the ultracentrifuge (mol. wt. ca. 85,000) but which 

 contains three components as judged by electrophoresis. The active 

 fraction contains over 70 per cent of the total protein and emits light 

 only when reduced FMN, aldehyde, and oxygen are present. No 

 emission is observed with reduced DPN. 



The biochemical and physiological aspects of bacterial lumines- 

 cence have been reviewed recently, and only that evidence which 

 seems to be essential for a discussion of the mechanism will be 

 presented here. 



;:^ 210 



z 



UJ 



I 

 O 



150 



0.2 0.4 I 



DODECANAL CONC.-MxIO^ 



Fig 29. Rclationsliip between light intensity and akieliyde. Initial light in- 

 tensity, in arbitrary units, of a bacterial extract solution initiated by injection 

 of a constant amount of reduced DPN, but as a function of the concentration of 

 dodecanal in the solution. The insert is a Michaelis-Mentcn plot of the data, in- 

 dicating a simple relationship between aldehyde and initial rate of the rigiit re- 

 action. 



