关键词: 小米, 蛋白组分, 亚基, 二级结构

Abstract: The structures of 4 protein components in millet were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), scanning electron microscopy, differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR). This study showed that millet gliadin was composed of low-molecular-mass subunits (11–25 kDa), while albumin, globulin and glutenin subunits were widely distributed (11–180 kDa). Albumin contained the largest number of subunits. The prolamin, albumin and globulin molecules were closely linked and existed in an aggregated state, while the gluten molecules were loosely connected and had a smooth surface. The globulin was denatured at 71.33 ℃, and the prolamin had the highest denaturation temperature of 110.67 ℃. FTIR study showed that the secondary structures of the prolamin, gluten and globulin were mainly composed of β-sheet, accounting for 37.72%, 43.39%、42.23% of the total amount, respectively. The prolamin contained the most abundant structures of β-turn and antiparallel β-sheet, accounting for 16.64% and 12.73% of the total amount, respectively. However, the secondary structure contents of the four protein components were significantly different (P < 0.05).

Key words: millet, protein components, subunit, secondary structure