pH对小麦HMW-GS 1Dx5的N端结构域分子特性的影响

Effect of pH on Molecular Characteristics of N-Terminal Domain of Wheat HMW-GS 1Dx5

采用内源荧光光谱、总自由巯基定量、非还原和还原十二烷基硫酸钠聚丙烯酰胺凝胶电泳(SDS-PAGE)以及原子力显微镜(AFM)等方法探究了pH值对高分子量麦谷蛋白亚基(HMW-GS)1Dx5的N端结构域(1Dx5-N)聚集体形成的影响规律.结果显示:与酸性和碱性条件下相比,中性(pH=7.0)条件下,1Dx5-N的荧光最大发射波长发生了蓝移,表明中性条件下1Dx5-N聚集程度增加;与酸性和碱性处理条件相比,中性条件下1Dx5-N的总自由巯基含量降低,且形成了更多的二聚体和高聚体,表明中性环境更有利于1Dx5-N的聚集,且分子间二硫键对聚集体的形成发挥了重要作用;中性条件下形成了颗粒直径相对较大的聚集体,进一步证明了中性条件更有利于1Dx5-N的聚集.从而从分子层面证明了中性条件下进行面制品加工的合理性.

By means of intrinsic fluorescence measurements, total free sulfllydryl （SH） quantitation, non-reducing and reducing SDS-PAGE analysis and AFM, the effect of pH on the forming of the N-terminal domain aggregation of high molecular weight glutenin subunits （HMW-GS） 1 Dx5 （ 1Dx5-N ） was investigated. The results show that （ 1 ） in comparison with the acidic and alkaline conditions, the maximum emission wavelength of 1 Dx5-N displays a blue shift under the neutral pH condition （ pH 7.0） , indicating that 1Dx5-N under the neutral pH condition has a higher degree of aggregation; （2） in comparison with the acidic and alkaline conditions, the 1Dx5-N under the neutralcondition is of a lower total free sulfhydryl （SH） content with more dimers and gregatlo （3） un neutral n of 1Dx5-N, the neutral der the neutral pH con pH condition is superior to the rationality of the flour product n is more helpful and the disulfide polymers, indicating that, bonds play an important role ; the aggregation of greater particle size forms, which further proves the acidic and alkaline conditions in terms of the aggregation of 1 Dx5-N processing under the neutral condition is demonstrated at the molecular ag- and the Use