472 X, BILE PIGMENT FORMATION, ETC. 



miiller (in 1903) first observed the discoloration of hemoglobin by 

 bacteria, the so-called "a" or "viridans eflFect" {2I^61). Parisot {2106) 

 obtained a green pigment by the action of adrenaline on hemoglobin. 

 The transformation of hemoglobin into a green, ether-soluble bile 

 pigment by incubation with liver brei and liver extract (Schreus and 

 Carrie, 2If.70) has been mentioned above. Hart and Anderson {52, 

 1141) found, not only bacterial autolysates, but also a variety of 

 •hydrogen donors able to form an insoluble green pigment if hemo- 

 globin solutions were incubated with these extracts or substances in 

 the presence of air. Among these was ascorbic acid. Edlbacher and 

 von Segesser (6^7) later obtained a green, amyl alcohol-soluble sub- 

 stance by acid treatment of the green pigment obtained by coupled 

 oxidation of hemoglobin and ascorbic acid. At the same time the 

 reaction was studied in detail by Lemberg and co-workers {^92,1668, 

 1707-1710,1712). 



In the first stages hemoglobin is partly transformed into a green 

 water-soluble compound, which was called choleglobin. Later, when 

 the choleglobin concentration reaches about 20% of the initial hemo- 

 globin, free biliverdin is found in the solution, while the globin becomes 

 denatured, and a green surface scum and precipitate appear. This 

 is the "green pigment" of Anderson and Hart. It is essentially 

 denatured choleglobin, but differs from the substance obtained by 

 denaturation of choleglobin with alkali by having its prosthetic group 

 firmly attached to the denatured protein. Finally, 10-15% of the 

 prosthetic group of hemoglobin can be obtained in the form of bili- 

 verdin. These results were confirmed later by other workers {691, 

 1527). 



4.2. Properties of Choleglobin 



4.2.1. Spectroscopic Properties. Choleglobin has so far been 

 obtained only in mixtures with a great excess of hemoglobin. Its 

 spectroscopic properties can, therefore, only be studied in regions 

 of the spectrum in which hemoglobin has little absorption. The 

 "green pigment," however, could be obtained practically free from 

 denatured globin hemochrome. Table II shows the position of the 

 typical absorption bands of choleheme compounds. Despite the 

 identity of position of the bands of carboxycholeglobin and chole- 

 globin, the formation of a carboxy compound could be established; its 

 absorption band is higher than that of choleglobin. Attempts to 

 demonstrate a reversible combination with oxygen failed, since 



