Partial amino acid sequence of gamma-46 gliadin.

We have determined the partial amino acid sequence (207 amino acids) of gamma-46 gliadin isolated from wheat cultivar Hardi. The molecular mass of the protein (Mr) estimated by electrospray mass spectrometry is 35191.3. The number of cysteine residues in gamma-46 gliadin was determined as a mass difference of the protein before and after reduction and alkylation with 4-vinylpyridine. It was shown that the protein has no free SH-groups, and all cysteine residues are involved in the formation of four disulfide bonds. The partial structure of gamma-46 gliadin was determined by N-terminal sequencing and sequencing of tryptic and chymotryptic peptides. The tryptic peptides were obtained by enzymatic hydrolysis of the protein, which was preliminarily reduced and immobilized at free SH-groups on thiopropyl-Sepharose 6B. The chymotryptic peptides were isolated by limited digestion of the native protein. The positions of cysteine residues, as well as surrounding amino acid sequences, are conserved in gamma-46 gliadin; this is typical of gliadins.