THE CHEMISTRY OF LIGHT PRODUCTION 137 



pressure of is sufficiently high. If luciferase is also 

 present we have luminescence. 



LH2 + O + luciferase ^ L + H2 O + luciferase (luminescence) 



The reaction proceeds in the left hand direction under 

 low oxygen pressure, in the presence of nascent hydrogen 

 or with some catalyzer which is able to split water, trans- 

 ferring the H2 to oxylucif erin and the to an acceptor ( A) . 

 NaHgPOa plays the part of the acceptor. 



L + H2O + A + Pd = LH2 + AO + Pd. 



This appears to be the way in which the reducing 

 enzymes or perhydridases (comparable to the Pd) of liv- 

 ing tissues act (Bach, 1911-13) and the action of yeast 

 cells, bacteria, muscle suspensions, etc., in reducing oxy- 

 lucif erin must occur in the same manner. 



If we assume that the LH2 (luciferin) compound is dis- 

 sociated to even the slightest extent into L and hydrogen, 

 the hydrogen ion will shift the equilibrium toward the 

 formation of that substance which involves the taking up 

 of hydrogen. Consequently we may obtain a partial for- 

 mation of luciferin by adding an acid to oxylucif erin. Re- 

 duction of the H-ion concentration tends to shift the 

 equilibrium in the opposite direction. Consequently, 

 addition of alkali favors the oxidation of luciferin, and it 

 is quite generally true that biological oxidations are 

 favored by an alkaline reaction. In addition oxygen in 

 alkaline medium has a higher oxidation potential than in 

 jieutral or acid media. I believe this is the expla- 

 nation of the action of acid in formation of luciferin 

 from oxyluciferin. 



Addition of acid is not the only means of favoring 

 the formation of luciferin from oxyluciferin. Any reac- 



