408 CORRADO BAGLIONI 



on tlie liltcr paper and tailing of the hemoglobins may j^reohide the 

 observation of minor components ha\ing an clectrophoretic mobility 

 lower than the major components. Filt(M- i)aper electrojihoresis is still the 

 simplest and fastest method of analysis for the detection of major 

 components if a lai'ge number of samples have to be analyzed. The 

 clectrophoretic analysis on agar gels has also been ap])lied to the separa- 

 tion of hemoglobins (see review by Gratzer and Beaven, 1961). 



Chromatographic methods of analysis of human hemoglobin on ion 

 exchangers have also been developed; these methods offer better resolu- 

 tion and quantitative isolation of the separated components. The pres- 

 ence of minor components in samples of human hemoglobin has been 

 confirmed by several investigators, using different analytical techniques 

 for protein separation. Huisman and JMeyering (1960) have standardized 

 the chromatographic separation on caiboxymethylcellulose, described by 

 Peterson and Sober (1956), for the qualitative analysis of human hemo- 

 globin and for the preparative isolation of the components. 



Morrison and Cook (1955) demonstrated by chromatography on the 

 resin IRC-50 that normal adult hemoglobin is heterogeneous; Prins and 

 Huisman (1956) also detected heterogeneity of human hemoglobin in 

 the same way. The chromatographic method of analysis on IRC-50 has 

 been greatly developed and improved by Allen et al. (1958) and subse- 

 quently by Clegg and Schroeder (1959) and by Schnek and Schroeder 

 (1961); several minor components are separated by this method of 

 analysis. 



The separation of human hemoglobins by starch block electrophoresis 

 and by column chromatography has considerably complicated the prob- 

 lem of the identification of components isolated by different techniques 

 and the problem of nomenclature. 



The original system of nomenclature proposed by Kunkel and Wal- 

 lenius (1955) has been the most widely accepted. The major component 

 isolated by starch block electrophoresis has been designated Ai by these 

 authors; it represents approximately 90% of the total hemoglobin. The 

 most slowly moving hemoglobin component in electrophoresis has been 

 designated A2 and the most rapidly moving A.j; they represent 2-3% 

 and 4-12% of the total hemoglobin, respectively. It has become cus- 

 tomary to indicate the major component as hemoglobin A or in shortened 

 form as Hb-A. However, the two minor components are still indicated 

 as Hb-Az and Hb-A^. Keys to the identification of the minor components 

 isolated by starch block electrophoresis with the components isolated 

 by column chromatography are found in the articles of Schnek and 

 Schroeder (1961) and of Huisman and Meyering (19601. 



