492 X. BILE PIGMENT FORMATION, ETC. 



7.3. Protein of Sulfhenioglobin 



The globin of sulfhenioglobin is apparently essentially unchanged 

 (1945) ; its molecular weight is 68,000. The rate of alkali denaturation 

 of human and bovine sulfhenioglobin is the same as that of the 

 corresponding hemoglobins, and so are the solubilities in water and 

 phosphate buffer, the isoelectric points, and the cataphoretic mobil- 

 ities. Michel was unable to obtain a separation of mixtures prepared 

 in vitro as well as from the blood of rats fed sulfur and phenacetin. 

 Lemberg and co-workers (1701), however, observed an enrichment 

 of sulfhemoglobin in the mother liquors of the crystals obtained from 

 hemolyzed rats' blood. 



7.4. "Sulfhemoglobin" as a Mixture of Sulfhemoglobin 

 and Choleglobin 



Clarke and Hartley (J^54) stated that sulfhemoglobin is unstable and, 

 even at 0° C. yields a compound with the absorption band of hemoglobin, 

 but not identical with it. Michel (lOJfo) observed a drop of only 3.6% in 

 the absorption of protohemochrome, obtained from sulfhemoglobin with 

 alkali and dithionite, accompanying a 30% conversion of hemoglobin into 

 sulfhemoglobin, while a proportionately far greater drop (30%) accompanied 

 a 7.5% conversion. In the course of the conversion to sulfhemoglobin the 

 oxygen uptake went on even when the rate of increase in sulfhemoglobin 

 concentration had become small. 



Lemberg and co-workers {1701) have shown that sulfhemoglobin 

 prepared in vitro is a mixture of true sulfhemoglobin, reconvertible 

 into protohemochrome, and choleglobin or a choleglobin-like sub- 

 stance, which on denaturation by alkali yields a compound spectro- 

 scopically identical with denatured globin choleheniochrome (absorp- 

 tion band at 618 m/z). In human blood containing sulfhemoglobin, 

 no choleglobin was detected, and the sulfhemoglobin prepared by 

 brief action of hydrogen sulfide on oxyhemoglobin is also almost free 

 from choleglobin. On prolonged action, however, and particularly 

 with alkali or ammonium sulfides (at higher 7:>H), choleglobin is pre- 

 dominant. This was also found by Barkan and Walker {168) and 

 by Haurowitz {1171); Nijveld {205Ji) showed that the compound 

 formed from hemoglobin with hydrogen sulfide and hydrogen peroxide 

 is mainly choleglobin. 



The claim of Jung (H-S9) and von Restorff {2230) that sulfhemoglobin is 

 usually nothing but "verdohemochromogen" is erroneous, apart from the 

 incorrect use of the term "hemochromogen" for an undenatured protein. 

 The confusion may have been caused by a faulty spectrophotometer which 



