W. I). McElJiOY AM) H. H. SELIGER 



235 



1300 

 1200 

 I 100 

 1000 

 900 

 en 800 



3 700 



I- 



g 600 



Zi 



500 



400 



300 



200 



100 



pH 



Fig. 13. Eflert of /;H and buffers on light emission. The upper tune is for glycine 

 buffer and the lower curves for phosphate buffers (Na+ and K+). 



mixtures were degassed, and oxygen was added to the concentration 

 indicated in the table. The particular gas mixture was bubbled con- 

 tinuously, and the light intensity was measured after the enzyme was 

 added to start the reaction. The intensities observed at these vari- 

 ous oxygen concentrations and at various time intervals are indicated 

 in the figure. After the reaction had run for approximately 2V2 

 minutes, oxygen was added to the reaction mixture and the resulting 

 flash was recorded. The peaks of these flashes are indicated in the 

 table. These results are taken to indicate that oxygen plays an im- 

 portant role in the reaction leading to light emission. In addition, 

 it can be demonstrated that under anaerobic conditions some active 

 intermediate accumulates which then rapidly reacts with oxygen when 

 the gas is readmitted to the reaction vessel. A large amount of ex- 



