Identification of gamma-type hordeins in barley

The barley mutant Risϕ 56 has a deletion of at least 85 kb of DNA at the Hor 2 locus, resulting in the absence from the seeds of almost all of the major B hordein group of storage proteins. We have purified two fractions containing the three remaining ‘B hordein-like’ bands and determined their N-terminal amino acid sequences. One fraction, containing the two bands with higher Mr, gave a single major N-terminal sequence which was closely related to those reported for γ-type prolamins of wheat and rye. The sequence of the third band was also homologous with those of the γ-type prolamins, but less closely so. We consider that the γ-type prolamins are most closely related to the ancestral S-rich prolamins of the Triticeae, and this is the first report of their presence in barley.