稻米胚芽_____稻米胚芽，谷氨酸脱羧酶，光谱分析

稻米胚芽谷氨酸脱羧酶的光谱分析

http://www.100md.com 《分析化学》 2006年第5期

稻米胚芽,,稻米胚芽，谷氨酸脱羧酶，光谱分析,摘要,关键词,1引言,2实验部分,3结果与讨论,References

     摘要

    从稻米胚芽中分离纯化得到谷氨酸脱羧酶(GAD)，经十二烷基磺酸钠聚丙烯胺凝胶电泳(SDSPAGE)、体积排阻高效液相色谱测得米胚GAD为双亚基组成，其相对分子质量为78000，亚基分子质量为40000；紫外可见光谱特征为420 nm处的弱吸收峰，这是辅基PLP与米胚GAD主链结合后产生的；荧光光谱主要表现为Tyr残基的荧光特征，脱辅基前后的荧光光谱完全相似；圆二色谱分析表明，在二级结构中,α螺旋占13.2%， β折叠占38.3%，是一种高β折叠蛋白，脱辅基后蛋白质的二级结构的变化不大。

     关键词 稻米胚芽，谷氨酸脱羧酶，光谱分析

    Spectroscopic Characterization of Glutamate Decarboxylase From Rice Germ

    Zhang Hui*1,2, Yao Huiyuan2

    (Key Laboratory of Food Science and Safety, Ministry of Education1,School of Food Science and Technology2, Southern Yangtze University, Wuxi 214036)

    Abstract After separating. and purifying the glutamate decarboxylase (GAD) from rice germ, its composition was analyzed as two subunits with a molecular weight of 40000 and 78000 respectively by sodium dodecyl sulfonatepolyacrylamide gel electrophoresis (SDSPAGE). (Similar molecular weight was 78000 obtained by sizeexclusione high performance liquid chromatography (SEHPLC)). Spectral analysis was performed on the GAD to research its further properties. Absorption spectrum of GAD shows one weak peak appears at 420 nm, it is produced by the binding of pyridoxal5′phosphate (PLP). Fluorescence emission spectrum of GAD was characterized by a Tyr peak waved around 308 nm, and has no change after PLP removed. Circular dichroism analysis of GAD shows that the ratios of αhelix and βsheet in the secondary structures are 13.2% and 383%. The secondary structures have a little change after PLP removed. ......

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