178 



BIOCHEMISTRY OF FIREFLY LUMINESCENCE 



of its properties studied. The enzyme required specifically Mg++ ion 

 as the activating metal and was inhibited by Mn++, Ca++, Be+ + , and 

 Cu++ (McElroy, Coulombre, and Hays, 1951), 



The fact that several compounds, in particular Mn++ and fluoride, 



12 3 4 5 



TIME (MINUTES) 

 Fig. 11. The response of the luminescent system to varying ATP concentration 

 and a constant (5 X 10" M) inorganic triphosphate concentration (McElroy, 

 1951a). 



can preferentially inhibit pyrophosphatase activity without affecting 

 luminescence indicates that this enzyme is not essential for light 

 production. The most highly purified luciferase reported above had no 

 pyrophosphatase activity associated with it. 



A variety of organic and inorganic phosphate compounds have been 

 tested for their ability to influence light emission in the enzyme prep- 



