216 



LIGHT AND LIFE 



sides in the recent discovery of a luminescent cross-reaction between 

 the luciierin and luciferase of a fish, Apogon, and the crustacean 

 Cypridina (16, 34). In this instance, the cross-reaction has been 

 studied both quantitatively (Fig. 2) and with purified preparations 

 of each system. The absorption spectra of chromatographically puri- 



10 20 30 40 50 



TIME (SEC.) 



60 



70 



lig 2. I.umincstcnt < ross-iciu lion of partially purilicd. highly ililuted luciferase of 

 Cyj>ridinit in 0.1 M phosphate hiifler. pH (i.H and 0.1 M NaC.l. with hiciferin of 

 the posterior photogenic organs of Ajjogoi} obtained by boiling the dried organs 

 momentarily in distilled water and then cooling rapidly. The data are plotted 

 in the manner of a reaction thai is lirsi order with respect to hiciferin concentra- 

 tion, a representing total light in arbitrary miits at the completion of the reaction, 

 and -v representing the amount of light emitted up to time /. Concentration of 

 luciferase used for 1) was double that which was used for .\, B, and C. Initial 

 hiciferin concentrations were in the proportion of 1 (curve .\), 0..") (curves B and 

 ])), and 0.2.') (cur\e C). \n abstract based in pari on these data has been pub- 

 lished (Hi). 



