11'. 1). Mr El. ROY AM) H. H. SELIC.ER 



237 



periiiiciital cvidciue indicates ihaL the material accumulated inider 

 anaerol)ic conditions is the enzyme-lucileryl-adenylic acid complex. 



A rapid recording ol the oxygen flash indicates that the shape of 

 the curve is very similar to the pseudo-flash of the intact firefly 

 which has been placed under anaerobic conditions. Although the 

 oxygen flash provides a model mechanism for normal flashing, the 



12 3 4 



TIME - MINUTES 



Fig. 10. The effect of oxygen concentration on tlie time course of luminescence. 

 Oxygen was added to the reaction mixture at 'ZV^ minutes, and the resulting flash 

 lieight was recorded as indicated in the table. 



duration of the oxygen flash is much longer than the normal fire- 

 fly flash. By varying the luciferin, luciferase, magnesium, ATP, or 

 oxygen concentration to obtain the flash indicated in Fig. 16 we 

 have not been able to obtain one which is typical of the normal fire- 

 fly flash. For this and other reasons we prefer the idea that the flash 

 in the intact firefly is due to a reversal of the inhibition of the enzyme 

 by pyrophosphate. 



