568 XI. HEMOGLOBIN CATABOLISM, I 



about 60% of the nonhematin iron of rats' liver can be precipitated by tri- 

 chloroacetic acid, while 40% is found in the solution; the latter reacts com- 

 pletely with thiocyanate. Libet and Elliot {1729) claim that a protein iron 

 compound, "ferrin," distinct from ferritin, is present in the liver of various 

 animals, but "ferrin" may be heat-denatured ferritin. In dogs' liver the 

 storage iron is certainly largely ferritin (Granick and Hahn, 1036). In addi- 

 tion the liver also contains some ferrous iron not bound to protein {£613). 

 Bull spermatozoa contain 40% hematin and 60% nonhematin iron {3181). 

 The importance of ferritin for the absorption of iron from the intestine will 

 be discussed in Chapter XIII, Section i.i. 



It is still not proved that all forms of histologically observed "hemosiderin" 

 are identical with ferritin. Ferritin has been found in the erythrocytes 

 (Agner, 28). 



10.4. FateofGlobin 



Little is still known about the fate of globin set free from hemo- 

 globin. Recently, Robscheit-Robbins and collaborators {2292) have 

 studied the electrophoretic mobility pattern of the plasma proteins 

 after intraperitoneal injection of hemoglobin. They found a prompt 

 increase of the peaks corresponding to /3-globulins and "fibrinogen," 

 followed by a decrease after discontinuation of hemoglobin adminis- 

 tration. "Modified human globin" had a mobility between those of 

 jS-globuIins and fibrinogen. It is unlikely that fibrinogen itself is 

 increased, as had been assumed by Fagerberg and co-workers {729); 

 rise of fibrinogen after tissue injury is accompanied by an increase of 

 as globulin, which was not found after hemoglobin injection. 



If the indirect bilirubin of the serum is bilirubin-globin {cf. Section 

 8.3.2.), globin is only removed from bilirubin in the liver. 



The occasional formation of denatured globin in erythrocytes, its 

 relation to the Heinz bodies, and the possible effects of this denatura- 

 tion on hemolysis have been discussed previously. The use which is 

 made by the body of the protein part of catabolized hemoglobin in 

 resynthesizing hemoglobin will be discussed in Chapter XIII. 



11. CATABOLISM OF HEMATIN ENZYMES 



Practically nothing is known about the catabolism of the respira- 

 tory ferment. From the fact' that copper is needed for its mainte- 

 nance {cf. Chapter XIII) one may conclude that it undergoes a con- 

 tinuous destruction and synthetic replacement. 



Since cytochrome c is not autoxidizable and does not combine 

 with oxygen, it is unlikely that it is transformed to bile pigments. 



