PROPERTIES OF SULFHEMOGLOBIN 491 



by many authors {7945Jf,1129,1156,139J^,H78,19^5). Haurowitz 

 (1156) obtained crystals, but in the Hght of later research it must be 

 considered very doubtful whether these contained unaltered sulfhemo- 

 globin. In many instances the preparations probably contained 

 sulfhemoglobin together with choleglobin or choleglobin-like sub- 

 stances (cf. Section 7.6.). Sulfhemoglobin is found in blood under 

 pathological conditions (cf. Chapter XII). 



7.2. Properties of Sulfhemoglobin 



Sulfhemoglobin has an absorption band at 620 m^t; some observers 

 have found it at 623-626 m/z {1156,16Jf), but this is probably due to 

 an admixture of choleglobin. Sulfhemoglobin does not combine 

 reversibly with oxygen but is oxidized to sulfhemoglobin, although 

 the ferrous form appears to be rather stable. On oxj'genation a 

 shift of the band from 620 to 632-633 m^ has been observed {1156, 

 164); this band is, however, probably due to hemiglobin, formed 

 from the accompanying hemoglobin under the conditions of the 

 experiment. 



Sulfhem/globin has been produced by Keilin (1478) and Nijveld 

 {2054) by oxidation of sulfhemoglobin with ferricyanide and can be 

 reduced again to sulfhemoglobin. If the absorption due to accom- 

 panying hemiglobin is subtracted, it is found that sulfhem/globin 

 does not have a distinct absorption band in the red part of the 

 spectrum {2054)- It appears to be a rather unstable compound 

 {1945,2054). Sulfhemoglobin combines with one mole of carbon 

 monoxide, the absorption band being shifted to shorter wavelengths 

 (612-618 m^). 



A complete conversion of hemoglobin into sulfhemoglobin has 

 never been achieved, but Drabkin and Austin {628) have extrapolated 

 its absorption curve, assuming that in the initial stages of the reaction 

 no other compound is formed. They found c^m = 11. There 

 appears also to be a somewhat lower and indistinct absorption band 

 at about 540 mii. Lemberg and co-workers {1701) found for carboxy- 

 sulfhemoglobin e^M = 16; from this value Jope {1437) calculates a 

 somewhat higher value for e^^^i of sulfhemoglobin (13.0) than that 

 found by Drabkin. 



Crystals of oxyhemoglobin containing up to 9% sulfhemoglobin 

 have been obtained by Michel {1945). 



