104 Papers from the Department of Marine Biology. 
from the class of hydrolyzed derived proteins (proteoses, peptones, and 
peptids). Of the seven groups of simple proteins, it can not belong to 
the globulins—because it is not precipitated on dilution with water or 
on half-saturation with (NH,4):5O,—or glutenins (because soluble in 
water), or prolamines (because insoluble in 70 per cent alcohol), or 
albuminoids (because of its solubility in aqueous solvents), or histones 
(because not precipitated by dilute NH,OH),or protamines (because 
coagulated on heating). There remain only the albumins and the 
groups of conjugated proteins—the glycoproteins (mucins and mucoids). 
nucleoproteins, phosphoproteins (caseins), lecithoproteins (vitellins), 
and chromoproteins. It is not a chromoprotein (because not colored), 
or a vitellin-like protein which has properties similar to the globulins, 
or a nucleoprotein, casein-like or mucin-like protein, because not pre- 
cipitated by dilute acetic acid and because coagulated on boiling. It 
is not a mucoid (similar to the mucins but not precipitated by acetic 
acid) because coagulated on boiling. The latter contains a carbo- 
hydrate group, but I can not state definitely at the present time 
whether pure luciferase contains a carbohydrate group or not. There 
remains only the group of albumins, with which the properties of 
luciferase agree completely. 
Dubois believes Pholas luciferase to be an oxidizing enzyme similar 
to the oxydones of Batelli and Stern,! because it is readily destroyed by 
fat solvents, such as chloroform, strong alcohol, ete. He has detected 
iron in a luciferase solution which has dialyzed against running water 
for a long time and believes it to be made up of protein in combination 
with iron and to act as an ‘‘oxyzymase ferrique.”” Cypridina lucif- 
erase, on the other hand, is not readily destroyed by fat solvents. 
Toluol and chloroform are good preservatives and I often make use of 
them for this purpose, keeping the luciferase solutions for many months. 
Professor A. H. Phillips, of Princeton University, has very kindly 
analyzed some whole, dried Cypridine for me and finds iron, copper, 
and manganese, but no zinc or vanadium present. Whether these 
metals are connected with the action of Cypridina luciferase is un- 
certain, but it is a significant fact that all three metals concerned in 
oxidations occur in the animal. 
Although a large amount of luciferin mixed with a small amount of 
luciferase will use up all of the latter,’ I agree with Dubois that lucif- 
1 Batelli, A., and Stern, Biochem. Z., 1914, Ixvii, 443. 
2 Dubois, R., Ann. Soc. Linn. de Lyons, 1914, lxi, 161. 
3If one mixes concentrated luciferin and weak luciferase the light which appears will last a 
long time before going out. After the light disappears, if one dilutes this mixture with water or 
adds more luciferin no further luminescence occurs, but if one adds more weak luciferase, light again 
is produced and lasts a considerable time. The fact that no more light appears on diluting the 
concentrated luciferin-weak luciferase mixture with water shows that the enzyme has not been 
inhibited by reaction products. If so, the dilution of these reaction products should allow the 
system to proceed to a new (false) equilibrium with production of light. Dubois (Ann. Soc. Lynn. 
de Lyon, xlix, 105, 1917) has misunderstood my statement fn regard to this. 
