BILE PIGMENT HEMATIN IN LIVER CATALASE 499 



reactions most useful for this purpose are collected in Table IV. If 

 one also remembers that hemiglobin and sulfhemoglobin (except in 

 severe anaerobic septicemia) and also choleglobin occur intracellu- 

 larly, while ferrihemalbumin is found only in the plasma, the differ- 

 entiation is still easier. 



8. VERDOHEME AND CHOLEHEME COMPOUNDS 

 IN HEMATIN ENZYMES 



8.1. Verdohemochrome Formed from Cytochrome c 



Bigwood and Thomas {2-jS) observed two absorption bands at 675 and 

 645 m/i in solutions of cytochrome c. The first band disappeared on reduc- 

 tion, but the second remained. These bands are probably due to a substance 

 related to choleglobin. Lemberg and Wyndham {1716) isolated small 

 amounts of verdohemochrome from preparations of cytochrome c. These 

 substances are not present in cytochrome c, but were formed from it during 

 the isolation, which involved reduction with dithionite and reoxidation. 

 Even the purest preparation of cytochrome c, however, contains a small 

 percentage (1-4%) of easily detachable iron (Theorell and Akesson, 2782). 

 Dihydroxymaleic acid in the presence of manganese destroys cytochrome c 

 rapidly with the formation of verdohemochrome (2791). The dihydroxy- 

 maleic acid reduces ferricytochrome to ferrocytochrome and at the same 

 time by its autoxidation — catalyzed by manganese — yields hydrogen 

 peroxide, which oxidizes cytochrome c to a verdohemochrome. The reaction 

 is completely' inhibited bj' catalase. 



8.2. Bile Pigment Hematin in Liver Catalase 



The isolation of biliverdin from horse liver catalase has been 

 discussed in Chapter IX. Evidence has been given that an inactive 

 bile pigment catalase is formed from the active protohematin catalase 

 by the action of hydrogen peroxide in the presence of reducing sub- 

 stances and that this bile pigment catalase is the precursor of the 

 biliverdin. It remains to discuss the nature of the bile pigment 

 hematin catalase more closely. 



Lemberg and Wyndham found that strong solutions of horse liver 

 catalase, after treatment with pyridine and dithionite, showed an 

 absorption at 651 m/n in addition to the bands of protohemochrome. 

 The same band was observed if alkali-denatured horse liver catalase 

 was cautiously reduced by dithionite (Lemberg and Legge, 1705). 

 Carbon monoxide formed a carboxy hemochrome which showed an 

 absorption band at 630 mn with a minimum at 690 m^ and rising 

 absorption toward the infrared. Removal of the carbon monoxide 



