Differential protein accumulation during barley grain development

Barley grains were analysed during development for the presence of salt-soluble proteins, hordeins and glutelins. Characteristic temporal differences between the fractions were observed with hordeins being produced relatively late during maturation. Analysis of this fraction by gel electrophoresis revealed differential accumulation of its component polypeptides. The C hordeins made up a relatively higher percentage of total hordein at the early stages, decreasing from 20% of the total at 33% final dry weight to 15% at maturity. The relative amount of the lowest molecular weight B hordein band (Bl) increased throughout development from 30% of the total at 33% final dry weight to about 45% at maturity. Electrophoresis of the salt-soluble fraction showed that a group of low molecular weight polypeptides appeared at the same stage of development as did the hordeins. There were only relatively minor changes in the polypeptide composition of the glutelin fraction.