METHEMALBUMIN 243 



bases with the carboxylic acid side chains could not be detectable 

 in the hemoglobin spectrum. 



3.3.5. Methemalbumin (Ferrihemalbumin). The only com- 

 pound of biological importance in which the linkage is probably from 

 the carboxylic acid side chains of the hematin to basic groups in the 

 protein is hemalbumin. Fairley {731) observ^ed that a pigment was 

 present in the plasma of patients with black water fever, which 

 appeared to be similar to hemiglobin (methemoglobin) and which was 

 originally named "pseudomethemoglobin" and later methemalbumin. 

 J. Keilin used the term "hematin-albumin"; in accordance with the 

 general principle of nomenclature used in this book we shall use the 

 term ferrihemalbumin. 



A positive reaction following Schumm's test for "hematin" in 

 plasma (addition of ammonium hydrosulfide with consequent forma- 

 tion of ammonia hemochrome) indicates the presence of ferrihemal- 

 bumin, this compound reacting more readily than does free hematin. 

 Heilmeyer indeed {1209) had observed that the spectrum of the 

 compound in the serum of patients suffering from pernicious anemia 

 and from hemolytic anemia differed from that of hematin in alkaline 

 solution, but he did not follow up his observations. Fairley has 

 shown {735) that the compound may be formed by the addition of 

 hematin to human serum or plasma. In the case of other animals, 

 the spectrum of hematin persists, but later experiments indicate that 

 combination also occurs. He then showed that serum albumin was 

 the protein responsible for the reaction.* The physiological role of 

 hemalbumin will be discussed in Chapter XII. The spectrum of 

 ferrihemalbumin has bands at 623, 540, and 500 mju, while reduction 

 to ferrohemalbumin gives a two-banded spectrum, 570 and 530 m/x- 

 The latter compound is not a hemochrome but may be transformed 

 by alkali into denatured albumin hemochrome with typical bands 

 at 558 and 524 mn. Ferrohemalbumin combines with carbon monox- 

 ide to give carboxyhemalbumin, whose spectrum is similar to that 

 of carboxyhemochrome or carboxy hemoglobin. The spectral change 

 when ferrohemalbumin combines with carbon monoxide may be 

 compared with the sharpening and shifting of the absorption bands 

 observed when caffeine heme combines with carbon monoxide. 

 J. Keilin considers that the increased affinity for nitrogenous base, 

 which the iron atom in heme shows in combination with carbon 



* It is not certain, however, whether the albumin is the only plasma protein able 

 to combine with hematin (c/. Miller and Ailing, 191f9a). 



