高效液相色谱-等离子体质谱联用方法研究富硒大米中硒的形态

根据Osborne溶解性蛋白质分类法,用去离子水、2%NaCl溶液、70%乙醇、0.5%KOH4种溶液分别提取出大米中相应的清蛋白、球蛋白、醇溶蛋白及谷蛋白。利用电感耦合等离子质谱(ICP-MS)测量各类蛋白提取液中的硒含量;用色谱与质谱联用法对大米蛋白提取液中含硒蛋白组分及含硒氨基酸组成进行初步分析。结果表明:大米中的硒主要与蛋白质结合,在4类蛋白提取液中硒含量由高到低的分布顺序为:谷蛋白、醇溶蛋白、清蛋白和球蛋白。清蛋白提取液中,分子量为12.6 kDa蛋白是主要的含硒蛋白组分;大米中约30%的硒以硒代半胱氨酸形式存在。

Study of Selenium Species in Selenized Rice Using High Performance Liquid Chromatography-Inductively Coupled Plasma-Mass Spectrometry

On the basis of Osborne fractionation,albumin,globulin,prolamine,and gluletin in selenium(Se) rich rice were extracted with water, 2% NaCl solution,70% alcohol,and 0.5% alkaline solution subsequently.The content of Se in these protein extracts was determined by inductively coupled plasma mass spectrometry(ICP-MS).The chemical forms of Se in albumin extract and enzymatic digests of rice were analyzed with a hyphenated technique of high performance liquid chromatography and ICP-MS.The Se content in four types of extracts shows an order of gluletin>prolamine>albumin>globulin.The protein with molecular weight of 12.6 kDa is the primary Se-containing protein in extracts of albumin,and the Se from selenocysteine is approximately 30% of the total Se present in the selenized rice.