Studies on The Chemical Structure of Bacterial Glutamyl Polypeptides by Hydrazinolysis

Abstract

During the investigation of the studies on the natural resistance against anthrax disease, the author found that dog liver extract hydrolyzed M-GPP* and S-GPP but not A-GPP (1). This fact indicates that A-GPP is not identical with the GPP of other two species in its chemical structure. In the previous paper it was shown that A-GPP was solely composed of d-G1u, but S-GPP and M-GPP of both d- and l-isomers (2). This is in accordance with evidences of the presence of l-isomers in S-GPP shown by Camp Detrick group (3, 4) and by Bovarnick**. For the clarification of the chemical structure, it is also necessary to elucidate the kind of linkage. Such investigations have been made by several workers (5–13). Above all, the presence of α-linkage of glutamic residue in A-GPP was persisted by H a n b y and R y d o n (6), but all recent investigations showed that γ-linkage was predominant in S- and A-GPP. The author performed hydrazinolysis of polypeptides derived from three species for the elucidation of their chemical structure. Hydrazinolysis is a method originated by Akabori et al. (14) for the estimation of carboxyl terminal of protein. When protein is treated with anhydrous hydrazine at 100°, carboxyl terminal amino acid (or acids) is liberated as a free amino acid, but the other amino acid residues as amino acid hydrazides. If GPP is subjected to hydrazinolysis, it is expected that α-linked Glu residue is converted to α-H, γ-linked residue to γ-H and αγ-dilinked residue to αγ-H respectively. This communication describes the observation on hydrozinolysis of GPP.