MECHANISM OF CHOLEGLOBIN FORMATION 479 



carried out in weakly alkaline solutions {1701; cf. also 2054^,2863) . The iden- 

 tification of sulfhemoglobin with choleglobin or "verdohemochromogen" is, 

 however, unjustified and confusing. In Jung's paper {lJf39) "verdohemo- 

 chromogen" stands at different times for sulfhemoglobin, for choleglobin, 

 and for pseudohemoglobin {cf. Sections G and 7.). 



The compound produced from hemoglobin by the action of arsine and 

 oxygen is probably choleglobin (Lemberg, 1684)* This reaction had first 

 been observed by Hoppe-Seyler in 1877 {1338) ; it was later studied by several 

 other workers {1156,1762,1896,2758). The assumption of Haurowitz and of 

 Thauer {1156,2758) that only hemoglobin is formed is erroneous. Oxygen is 

 required for the hemolysis of the erythrocytes by arsine {2013) as well as for 

 the transformation of hemoglobin into choleglobin. Henze {1244) found 

 that arsine and oxygen yielded hydrogen peroxide. The reaction is a coupled 

 oxidation, arsine being oxidized to arsenite {cf. 1027), while in the absence of 

 oxygen hem/globin is reduced to hemoglobin (Wolff, 3117; Jung, 1440). The 

 easily detachable iron in blood is increased by treatment with arsine. 



Finally, certain enzyme systems are evidently able to react in the same 

 manner as reducing substances. Such enzyme systems have been found in 

 bacteria {cf. Section 4.4.5.). Recently Kesztyiis and Kiese {1522) have 

 found that enzyme systems of liver pulp and liver extracts transform hemo- 

 globin into biliverdin {cf. also Schreus and Carrie, 2470). The heat-stable 

 substrate could be removed by dialysis, the enzyme, by ammonium sulfate 

 precipitation. A green hemoglobin is an intermediate product; it is more 

 readily converted into biliverdin than is hemoglobin, and at -pH 5.2 it yields 

 biliverdin while hemoglobin does not do so. Enzyme systems producing 

 hydrogen sulfide are indeed known to occur in the liver. Polonovski {2162) 

 has recently claimed that in the spleen choleglobin is formed, whereas in the 

 liver sulfhemoglobin arises as an intermediate product, f In the circulating 

 erythrocyte, however, sulfhemoglobin is quite stable and is not broken down 

 to bile pigments {cf. Chapter XI, Section 3.2.3. and Chapter XII). 



I'rine contains a substance which forms choleglobin {1688,1867), not only 

 hem/globin {2252), from oxyhemoglobin. 



The identity with choleglobin of the green hemoglobins formed in 

 these reactions has not yet been proved. The mode of their formation, 

 however, their properties, and in some instances their transformation 

 into bile pigments, make it appear far more likely that they are 

 choleglobin than that they are pseudohemoglobins (Section 6.) or 

 sulfhemoglobin (Section 7.). The green hemoglobin formed by 

 phenylhydrazine has spectroscopic properties differing slightly from 

 tho.se of choleglobin {1527,1529), but, like the latter, yields biliverdin 

 with acids. 



Other substances which form green hemoglobins in vivo are 2,4- 



diaminotoluene, w-dinitrobenzene, hydroxylamine, hydrazine, glycol 



* Kiese (1.526a) claims that it is sulfhemoglobin. 

 t Cited from abstracts onlv. 



