210 



VI. HEMOGLOBIN 



hemiglobin as ferric hemoglobin; the latter possibility was raised as 

 an objection against the use of hemiglobin instead of ferrihemoglobin 

 by Drabkin. (Oxy- and carboxyhemoglobin are so well known to be 

 ferrous compounds that the "o" need not be italicized.) Myohemt- 

 globin then represents the ferric form of muscle hemoglobin or 



Oxyhemoglobin 

 Carboxyhemoglobin 



j.co)\V 



Hemoglobin 



oxidation 



(Os, 



Hemiglobin 

 cyanide (hydroxide) 



// (CN~ OH") 

 Hem?globin 



denaturation 



Hematin renaturation I denaturation 



Denatured globin 

 Hemochrome 



Denatured globin 

 Hemichrome 



oxidation 



Fig. 1. interrelationship of hemoglobin derivatives. 



myomethemoglobin. The same nomenclature is used for compounds 

 such as sulfhemoglobin and sulfhemiglobin. 



We shall use the symbols Hb and Hi for hemoglobin and hemi- 

 globin, respectively, in formulas of their compounds with other 

 addenda. This is the simplest way to make the iron valency clear in 

 symbols for all hemoglobin compounds. 



Similar usage could also be introduced for the invertebrate hemoglobLns, 

 for example, erythrocruorin and erythricruorin or chlorocruorin and chlori- 

 cruorin for the reduced and oxidized forms, respectively, and might even be 

 extended to cytochrome (cytochrome and cytichrome). At the present junc- 

 ture we shall not extend the o-? principle to these compounds. It may also 

 be pointed out that it is not of general applicability (r/. peroxidase, catalase) 

 in the class of the hematin enzymes. For all these compounds the nomen- 



