UBC Theses and Dissertations
The terminal groups of the human and bovine [gamma]-globulin Lay, Woo-Pok
Sanger's dinitrophenyl method has been applied to human γ-globulln. One mole each of aspartic acid and of glutamic acid have been identified as the free α-amino terminal residues. In bovine γ-golubin, free amino groups are located on five different amino acid residues, namely, aspartic acid, glutamic acid, serine, alanine and valine. Each is present in sub-molar quantity indicating that the protein is heterogeneous with respact to N-terminal groups. By a combination of the carboxypeptidase and of the hydrazinolysis methods, one mole each of serine and glycine have been established as the C-terminal amino acids of human γ-globulin. The free carboxyl terminal groups of bovine γ-globulln also have been found to be serine and glycine. Carboxypeptidase erperiments indicate that there is no difference in the release of free amino acid from bovine γ-globulin and human γ-globulin. The C-terminal sequence of these proteins is probably the same. In one chain, serine may be followed by leucine and valine.
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