410 



CORR.\DO BAGLIONI 



Fig. 1. Schematic representation of the arrangement of the peptide chains in the 

 hemoglobin molecule. (From Ingram and Stretton. 1959b; reproduced by permission 

 of the editor of Xature.) 



istic patterns and the comparison of patterns of peptides — fingerprints 

 — allows the detection of minor differences in the composition of the 

 proteins under analysis (see Fig. 2, A and B). 



The fingerprinting method has been modified by several authors, who 

 have adapted the same principle, i.e.. the two-dimensional separation by 

 ionophoresis and chromatography, to different tj'pes of ionophoresis 

 apparatuses or to different chromatographic systems. These methods of 

 analysis yield comparable results; in the author's experience the original 

 (Ingram's! method (1958) is to be recommended for its simplicity and 

 practicality. The use of a solvent system different from the one orig- 

 inally employed by Ingram ('19581 has been found advantageous (Bag- 

 lioni. 19611. 



The fingerprints of the isolated chains of Hb-A showed different 

 patterns of peptides, which taken together made up the pattern given 

 by whole hemoglobin (Ingram, 1958, 1959a ». The fractions were then 

 identified with the two t>'pes of peptide chains described by Rhinesmith 

 et al. ("1958). by determining their X-terminal sequence (Ingram. 1959a I. 

 A great deal about the primary" sequence of Hb-A has been learned 

 recently and the amino acid sequence of the two chains of Hb-A is now 

 completely elucidated. 



