176 BACTERIOLOaiCAL AND ENZYME CHEMISTRY 



capable of oxidation to the substance known as oxiurushic 

 acid tbus :— 



2Ci,Hi,02+ 30 = 2Ci4Hi803 + H^O 



Some ten years later Bertrand separated the juice into 

 laccol, an alcohol derivative which was soluble in alcohol, 

 and into the enzyme laccase which was insoluble in alcohol. 

 Laccol was found to oxidise spontaneously, but the rate 

 of oxidation was greatly accelerated when laccase was 

 present. 



Ad enzyme with the same properties was obtained from 

 many vegetables, especially mushrooms of various sorts. The 

 same enzyme also will oxidise numerous hydroxy and amido 

 derivatives of benzene to quinone : thus in the case of hydro- 

 quinone the following reaction takes place : — 



CeH,(OH), + = C,H,0, + H,0 



While the action of laccase, or an enzyme akin to it, is not 

 specific, in the sense that one reaction and one only can be 

 brought about by its intervention, yet it has its limitations, 

 and will only oxidise such bodies as are capable of yielding 

 quinols. It does not, therefore, oxidise tyrosin, the formula 

 of which, it may be remembered, is 



CeH^OHCHjCHNH^COjH 



and which would therefore require to be broken up completely 

 before a quinol could result from its oxidation. Tyrosin can, 

 however, be oxidised by a specific enzyme known as tyrosinase, 

 which had quite recently been investigated by Gortner. The 

 source of Gortner's enzyme was the meal worm. To obtain 

 the enzyme the larvee were ground in a mortar with chloroform 

 water, and the milky liquid strained through a cheese cloth : the 

 milky extract if kept a short time in the air rapidly darkens 

 on the surface, it remains white where not in contact with 

 oxygen. It was found that a soluble and insoluble tyrosinase 



