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, esculin and taurine. A 

 glance at the structural formula of esculin and taurine is 

 sufficient to emphasize the diverse nature of these 

 two substances. 



H H 



O H NHa 



HO-S-C-C-H 



i 



H H 



Taurine 



C=C-C=0 



I 

 C 



^\ 

 H^ \-0 



C C 



OH C C H 



OH + Glucose 



Esculin 



I believe that iu 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 Pholas preluoiferin and Pholas 

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

 of Ct/pridina oxyluciferin, and it seems more logical l^p 

 look for the presence of Pholas oxylucif eriu in one or both 

 of Dubois ' extractsi rather than believe that luciferin can 

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

 luciferase solution stands with the preluciferin solution 

 we would m 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 



