108 



THE NATURE OF ANIMAL LIGHT 



luciferase belongs to the hydrolases. Indeed, it proves 

 too much. Lucif erin must have an extraordinary chemical 

 structure if it can be formed by hydrolysis of such diverse 

 compounds as peptone, lecithin, escuiin and taurine. A 

 glance at the structural formula of escuiin and taurine is 

 sufficient to emphasize the diverse nature of these 

 two substances. 



H H 



C=c-C=o 



O H NH2 



HO-S-C-C-H 



C 



C 



■0 



H H 



Taurine 



H 



OH C C 



. \ c X 



%/ 



OH + Glucose 

 Escuiin 



I believe that in these experiments Dubois has been 

 working with an oxidation product of luciferin, what I 

 have called oxyluciferin, rather than a pro-substance. The 

 mode of preparation of PJiolas preluciferin and Pholas 

 co-luciferase is such as could be used in the preparation 

 of Cypridina oxyluciferin, and it seems more logical to 

 look for the presence of Pholas oxyluciferin in one or both 

 of Dubois ' extracts rather than believe that luciferin can 

 be formed from both taurine and escuiin. When the co- 

 luciferase solution stands with the preluciferin solution 

 we would in reality have not the formation of luciferin 

 from preluciferin, but the formation of luciferin from 

 oxyluciferin, by some reducing agent in the mixture. 

 Indeed, in a very recent paper Dubois (1919 c) takes the 



