w. D. Mcelroy axd h. h. selk.er 



225 



2 3 4 5 



TIME-MINUTES 

 Fig. 4. Light from LHo-AMP compared with light from luciferin and ATP. 

 LHo-AMP is in excess of enzyme. Note extreme product inhibition. Second addi- 

 tion of enzvme is indicated bv arrows. 



30 



36 



12 18 24 



SECONDS 

 Fig. 5. Effect of pyrophosphate on light emission from LH^,-.\MP. 



no appreciable light production; magnesium alone has no effect. 

 These results can be interpreted in terms of the reaction of pyrophos- 

 phate with E-LH2-AMP and E-L-AMP to produce free luciferin and 

 free oxyluciferin respectively, and ATP; that is, the reversal of the 



