308 



LIGHT AND LIFE 



LIGHT 



HYPOTHETICAL LUCIFERASE CYCLE 

 INVOLVING CATALYTIC ALDEHYDE 

 PARTiaPATION OR UTIUZATION 

 IN A NON- LUMINOUS 

 REACTION 



Fig. A 



aldehyde oxidase activity. But when you use purified enzyme, which I 

 insist on, the only time we see rapid aldehyde utilization is when you get 

 light emission. For that reason, we suggested that aldehyde is used in the 

 process of excitation. 



Dr. Racker: How about the reversal? 



Dr. McElroy: The reversal— you mean starting with the acid? You can- 

 not reverse it, even in the presence of light. ^Ou can do a (hemical reduction, 

 as a matter of fact, but that is an artific ial system. 



Dr. Sirkiiler: Aprojjos to the utilization of aldehyde under conditions in 

 which you get luminescence, it is well known that reduced flavin auto- 

 oxidizes (|uite readily to produce peroxide. Might it not be that peroxide 

 gives by-products in a non-enzymatic or e\en in an enzymatic reaction which 

 isn't directly connected with luminescence. 



Dr. McKi.ro's-: No. that is not (]uite right. You can actually run a control 

 for this type of experiment. Wni (an start non-enzymatically with reduced 



