500 X. BILE PIGMENT FORMATION, ETC. 



failed to reproduce the band at 651 mn, but yielded a hemochrome 

 with absorption band at 618 m/x. The positions of this band and that 

 of the carboxy compound at 630 mn are the same as those of chole- 

 hemochrome and carboxycholehemochrome, respectively, but the 

 absorption in the infrared is not a property of choleglobin. The 

 position of the band before treatment with carbon monoxide and the 

 fact that acid yields almost 100% of biliverdin make it appear more 

 likely that the hemochrome is a compound of the verdohemochrome 

 type. The nature of the irreversible alteration by carbon monoxide 

 is not yet understood. 



9. BREAKDOWN OF HEMOGLOBIN 

 AND MYOHEMOGLOBIN TO DIPYRROLIC COMPOUNDS 



In Chapter IV we mentioned pentdyopent and the bilifuscins, two 

 types of dipyrrolic pigments which are products of the metabolic 

 breakdown of hemoglobin and myohemoglobin. Pentdyopent (or 

 rather propentdyopent) is formed by the action of strong hydrogen 

 peroxide solutions on hemoglobin or hematin (Bingold, 372,273,377). 

 It does not occur physiologically and its formation under pathological 

 conditions may be due to an intensified mechanism of hemoglobin 

 destruction, which is different in principle from that which leads to 



-► 2HC 



Figure 13 



bile pigment formation only in that the oxidative opening of the 

 porphyrin nucleus occurs simultaneously at two opposite methene 

 groups (Fig. 13). Such a reaction might lead first to bilifuscins 

 (c/. Chapter IV) which, on further oxidation of the central methene 

 group, would yield propentdyopent. Fischer and von Dobeneck (807) 

 found far higher concentrations of hydrogen peroxide necessary for 

 the formation of pentdyopent than for bile pigment formation. 



