Amino acid sequence of a purothionin homolog from barley flour.

A purothionin homolog was isolated from barley flour and purified by CM-52 column chromatography. It showed potent lethal activity towards brewer's yeast and its complete amino acid sequence was determined to be as follows. Lys-Ser-Cys-Cys-Arg-Ser-Thr-Leu-Gly-Arg-Asn-Cys-Tyr-Asn-Leu-Cys-Arg-Val-Arg-Gly-Ala-Gln-Lys-Leu-Cys-Ala-Gly-Val-Cys-Arg-Cys-Lys-Leu-Thr-Ser-Ser-Gly-Lys-Cys-Pro-Thr-Gly-Phe-Pro-Lys. It thus consists of 45 amino acid residues with 8 cysteines. The number of amino acid residues and the positions of the 8 cysteines are identical with those of wheat purothionins. There is a high degree of homology in the primary structures of these proteins.