STRUCTURE OF VERDOHEME 

 A compound of the structure given in Figure 7: 



467 



Fig. 7. Possible intermediate. 



may have an absorption spectrum quite similar to that of verdohemochrome. 

 It is not impossible that it occurs as a stage of the formation of verdohemo- 

 chrome {cf. Fig. 3) and may be present as an impurity in verdohemochrome 

 preparations in which the reaction has not gone to completion. (Stier, 2666- 

 2667 a). 



The varying yield of biliverdin obtained by the action of acids on verdo- 

 hemochromes can perhaps be understood in this way. Certain preparations 

 lost all their iron readily when treated with acids and gave a yield of almost 

 100% of biliverdin {1716), while others showed signs of incomplete splitting 

 and gave rather poor bile pigment yields {1712). This cannot be explained 

 by the observation of Stier {2666,2667) who found that diacetylhemato- 

 verdohemochrome in the presence of an excess of hydrazine is slowly oxidized 

 further to a hemochrome with a similar absorption spectrum; on treatment 

 with acid, the latter yields a bilipurpurin, not a biliverdin. Lemberg and 

 co-workers {1712) often found small recoveries in spite of the fact that they 

 measured total bile pigment yield (biliverdin + bilipurpurin). The process 



■♦ H 



OH 



OH " OH 



Fig. 8. Further oxidation of verdohemochrome. 



observed by Stier can be largely avoided by careful technique in the prepa- 

 ration of verdohemochrome. It consists evidently in the oxidation of methene 



