E. NEWTON HARVEY 291 



luciferase will use up all the latter/^ I agree with Dubois that lucif- 

 erase has sufiEicient properties in common with the enzymes as a 

 class to be considered an enzyme. The peroxidases are well known 

 to be used up in the reactions they accelerate. All workers on enzymes 

 agree that the more enzymes are purified the less active they become. 

 The chemical procedures necessary to remove foreign material bring 

 about irreversible changes in the enzyme itself, a characteristic also 

 of many protein groups and of the colloidal state in general. This is 

 true in the case of luciferase, for the crude luciferase solution is the 

 most active preparation that can be obtained. 



I believe that Cypridina luciferase should be placed in a class of 

 oxidizing enzymes by itself — a group having the chemical reactions of 

 an albumin, possibly in combination with some heavy metal, and 

 which as far as we know, acts specifically on only one substance, 

 Cypridina luciferin. It resembles the plant peroxidases in resisting 

 the action of chloroform, toluene, etc., but will not oxidize any of the 

 hydroxyphenol or aminophenol compounds^"* so readily oxidized by the 



^"^ If concentrated luciferin and weak luciferase are mixed, the light which 

 appears will last a long time before going out. After the light disappears, if this 

 mixture is diluted with water or more luciferin is added, no further luminescence 

 occurs, but if more weak luciferase is added, light again is produced and lasts a 

 considerable time. The fact that no more light appears on diluting the con- 

 centrated luciferin-weak luciferase mixture with water shows that the enzyme 

 has not been inhibited by reaction products. If so, the dilution of these reac- 

 tion products should allow the system to proceed to a new (false) equilibrium with 

 production of light. Dubois {Ann. Soc. Linn. Lyons, 1917, Ixiv, 105) has mis- 

 understood my previous statement regarding this. 



^* Because of the ease with which many of these hydroxyphenyl compounds 

 undergo autooxidation, one must always compare the color produced by luci- 

 ferase solution with that produced in a control of boiled luciferase solution. I 

 find that a concentrated luciferase solution well shaken with chloroform and fil- 

 tered, which produced a brilliant light with luciferin, had no oxidative action on 

 phenol, a-naphthol, ^-phenylenediamine, ortol, orcinol, hydrochinon, resorcinol, 

 pyramidon, phloroglucin, pyrocatechol, gallic acid, benzidine, pyrogallol, gum 

 guaiac, amidol, tannin, or a-naphthylamine, either with or without H2O2. Dubois 

 {Ann. Soc. Linn. Lyons, 1914, xli, 161) reports oxidation of pyrogallol, tannin, 

 hydroquinone, guaiacol, Tromsdrof reagent, chlorohydrate of diaminophenol, 

 ^-phenylenediamine, and naphthol, naphthol B, and gum guaiac plus H2O2 by a 

 solution of Pholas luciferase. These results are of little value, however, as there 

 is no evidence that the oxidation is due to luciferase rather than the oxidizing 

 enzymes which one finds in cell extracts of all animals whether luminous or non- 

 luminous. 



