【摘要】 以70个有代表性的小麦品种,采用SDS聚丙烯酰胺凝胶电泳(SDS-PAGE)方法检测淀粉粒结合SBE IIb的品种间差异;并对SDS-PAGE凝胶中SBE IIb进行回收、复性和酶活性测定。结果表明,淀粉粒结合蛋白(SGP)中分子量为85kD的SGP-2是与淀粉粒结合的SBE IIb,具有淀粉分支酶活性;SBE IIb从淀粉粒释放并去除SDS后活性立即恢复,其活性高峰出现在花后21d左右;SBE IIb在小麦籽粒发育早期开始表达,不同发育时期表达量有差异,但其表达图谱在品种间没有差异,即编码SBE IIb的基因位点不具有品种的遗传多态性。更多还原

【Abstract】 To elucidate subcellular localization and genetic polymorphism of SBE IIb,the isoform of starch branching enzyme(SBE),in wheat grain and make insight into molecular mechanism of amylopectin biosynthesis.We identified the differences of SBE IIb among 70 wheat varieties using SDS polyacrylamide gel electrophoresis(SDS-PAGE),recovered SBE IIb from polyacrylamide gel and determined its enzymatic activities.The expression levels of SBE IIb were examined during grain-filling period.The result indicated that starch granule-bound protein SGP-2,was granule-associated SBE IIb with molecular weight of 85 kD.It possessed SBE activity when SDS was removed by acetone precipitation,which reached the highest activity at the 21th day after anthesis.SBE IIb expressed at the early developing stage of wheat grain and expression quantity exhibited differences in different developing periods.Notably,the expression profile of SBE IIb showed no differences among 70 varieties.更多还原