554 KINETICS OF BIOLUMINESCKNT REACTION. II 



it is quite high for this reaction, the values being about 4.5 for the 

 15-25° interval, and 3.0 for the 25-35° interval. Fig. 7 will indicate 

 the form of the records assumed in such a determination. From the 

 data of this experiment the value of ^lo is calculated by Snyder's^ 

 formula 



f — 1 h-k 



Qio 



Substitution of the observed values from the experiment in this 

 equation gives Qio = 4.625 for the 15-25° interval. The actual value 

 for 28-38° is found to be 2.851. 



DISCUSSION. 



The following out of the initial assumption of the work, namely 

 that light intensity at any instant is directly proportional to the 

 reaction velocity at that instant, has led to a fairly consistant picture 

 of what occurs in the course of the bioluminescent reaction in Cypri- 

 dina. The decay curve is seen to fulfill closely the theoretical expec- 

 tation for a monomolecular reaction the velocity of reaction is 

 found to be proportional to enzyme concentration, and the diminution 

 of substrate concentration affects only, as it should, the value of the 

 ;y-intercept, and not the slope of the straight line plotting. The 

 very consistency of the results points strongly to the truth of the 

 initial assumption, for which indeed there is a strong likeHhood, on 

 purely a priori considerations. I believe that the present obser- 

 vations will lend considerable quantitative support to the hypothesis 

 of Trautz. 



The monomolecular form of the decay curve indicates very clearly 

 that we are dealing here with an oxidation process similar to the 

 oxidation of leuco-methylene blue, as Harvey' has suggested, and not 

 with a process of the type of the well known oxidation of cysteine 

 to cystine by the dehydrogenation and union of two cysteine molecules. 

 A reaction of the latter type may be written 



2 R-S-H + 0-R-S-S-R + H2O. 



Presumably, with oxygen in excess, it would follow a bimolecular 

 form. In the reaction under discussion, however, as in the oxidation 



^ Snyder, C. D., Science, 1911, xxxiv, 415. 



' Harvey, E. N., The nature of animal light, New York, 1920, 128. 



