THE CHEMISTRY OF LIGHT PRODUCTION 133 



a little dilute acetic acid, HCl, HNQ.. or H2SO4 to it, a cer- 

 tain amount of reduction will occur. No reduction occurs 

 if the solution is saturated with pure hydrogen, even if 

 allowed to stand 24 hours. The action of the acid begins 

 when the solution of oxylucif erin, ordinarily slightly alka- 

 line (Ph = 9), is made neutral (Ph = 7.1) as indicated in 

 Table 9. The action of the acid must be on the oxylucif- 

 erin, as no lucif erin or other enzymes destroyed on boiling 

 are present. 



Table 9 



Effect of Acid on Reduction of Oxyluciferin 



Solution 



20 c.c. Oxyluciferin alone 



20 c.c. Oxyluciferin + .05 c.c. 



5 per cent, acetic acid 

 20 c.c. Oxyluciferin -f- .15 c.c. 



5 per cent, acetic acid 

 20 c.c. Oxyluciferin -H .30 c.c. 



5 per cent acetic acid 

 20 c.c. Oxyluciferin -|- .50 c.c. 



5 per cent, acetic acid 

 20 c.c. Oxyluciferin + .75 c.c. 



5 per cent, acetic acid 



Remarks 



Acid forms precipitate in 

 this oxyluciferin sol. 



Acid forms precipitate in 

 this oxyluciferin sol. 



Acid forms precipitate in 

 this oxyluciferin sol. 



* Light disappears quickly because of the effect of the acidity on the luciferase. 



It is possible that the action of bacteria (which pro- 

 duces CO2), muscle tissue (which contains lactic acid), 

 milk (in which lactic acid may be formed by bacteria), or 

 Mg + acid, in forming lucif erin, is not the result of their 

 reducing power but of their acidity. Fortunately we can 

 test this matter by the use of reducing fluids which are not 

 acid. If they also form luciferin from oxyluciferin, a 

 reduction must occur. Nascent H can be generated by 

 the action of NaOH on Al, or when finely divided Mg or Zn 



