TYROSIN IN THE FUNGI : CHEMISTRY AND METH- 

 ODS OF STUDYING THE TYROSINASE 



REACTION 



CARROLL W. DODGE 

 Formerly Rufus J, Lackland Fellow in the Henry Shaw School of Botany 



of Washington University 



Introduction 



That certain fungi turn blue or black on exposure to the a 

 and that this property is destroyed by heat has been known 

 for many years, Pallas (1771), Bonnet (1781), Saladin (1779), 

 and Bulliard (1791) having incidentally recorded observa- 

 tions of the fact. Macaire (1824), in a very extended memoir 

 on the subject, brought out nearly all the main lines of proof 

 of the essential features of the reactions involved, although 

 some of his data are better explained on the theory of enzyme 

 action which has developed since his time. Since his work 

 many additional facts have been ascertained, as may be seen 

 by the excellent review papers by Kastle (10), Clark (10, 

 '11), and Bach ('13), as well as by others of the Geneva 

 workers to be mentioned later. All of the work so far has 

 dealt almost exclusively with the formation of pigment, and 

 practically nothing is known of the actual chemical changes 

 beyond the fact proved by Macaire that oxygen was absorbed 

 and suggestions as to a partial oxidation of the side chain in 

 the case of tyrosin. 



This being the general situation, an attempt has been made 

 to determine some of the chemical changes taking place in 

 the reaction. After an extensive study of the available litera- 

 ture, it seemed best to attack the problem of the tyrosinase 

 reaction first, since this enzyme is more specific and much 

 more is known regarding the products of oxidation as they 

 have been studied in the animal organism. 



The outstanding fact in the chemistry of tyrosin is its low 

 solubility (1:2500), which necessitates refining many of the 

 ordinary chemical procedures in order to work with the acid 



Ann. Mo. Bot. Gard., Vol. 6, 1919 



(71) 



