Amino acid compositions and amino-terminal end groups of α and β chains from polymorphic hemoglobins of Pongo pygmaeus

Abstract

Four hemoglobins of Pongo pygmaeus, orangutans, were purified and separated by ion-exchange chromatography of hemolyzates. The α chains and β chains were separated by ion-exchange chromatography of globins. Amino acid compositions and amino-terminal end groups of two types of a chains, α A and α B, and two types of β chains, β A and β C, were determined. The amino acid compositions of the α chains are similar to those of human α chain, and the compositions of the β chains are similar to those of human β chain. Differences in the α A and α B chains of orangutan hemoglobin are: α A, 14 aspartyl and 6 glycyl residues; α B, 13 aspartyl and 7 glycyl residues. Differences in the β A and β C chains are: β A, 12 lysyl, 11 glutamyl, and 16 alanyl residues; β C, 11 lysyl, 12 glutamyl, and 15 alanyl residues. These differences are consistent with charge differences inferred from relative electrophoretic and Chromatographic mobilities of intact hemoglobins and isolated chains. Valine is the amino-terminal end group of each chain.