Identification of γ-type hordeins in barley

AbstractThe 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

Specificity of an antibody to a subunit of high-molecular-weight storage protein from wheat seed and its reaction with other cereal storage proteins (prolamins)

An antiserum to subunit 2 from the high-molecular-weight (HMW) subunits of the glutenin fraction of Triticum aestivum cv. Highbury was shown to react with related subunits from other cultivars of wheat. The reaction was measured quantitatively by laser nephelometry in polyethylene glycol phosphate-buffered saline after dissolving the HMW fraction in 0.1 M acetic acid; urea used to dissolve the HMW prolamins inhibited the reaction, in some cases at the low concentration of 0.06 M. A study of the comparative reactions of other cereal prolamins was made. ‘D’ hordein, the homologous HMW protein of barley, showed less reaction, which was more inhibited by urea than the wheat subunits. Some ω-gliadins from the wheat cultivars Chinese Spring and Cheyenne reacted more strongly than the injected fraction and there was less inhibition by urea. A-, β- and γ3 of wheat also reacted with the antiserum while a secalin of rye of Mr 40000 gave a weak reaction. RESP-919