毕赤酵母表达硒代重组人血清白蛋白的研究

本试验将能够成功表达重组人血清白蛋白(rHSA)的巴斯德毕赤酵母培养至诱导期后，流加亚硒酸钠，同时设空白对照发酵液(不加入亚硒酸钠)，通过对比相同菌株在两组培养基中表达的rHSA的含硒量，判断硒能否以硒代氨基酸的形式存在于重组蛋白质中。发酵液经热处理、超滤、离子交换和丙酮沉淀等步骤后，进行Tricine-SDS-PAGE凝胶电泳、X射线能量色散谱(EDX)和原子吸收分析。结果表明，加硒发酵液样品中硒元素的质量分数比对照多23.2%，硒与蛋白质的质量比为0.0069，高于对照发酵液近35倍，初步证明无机硒可以被毕赤酵母同化，转化为硒代氨基酸，并形成硒代重组蛋白质。

Selenium incorporation into recombinant human serum albumin in Pichia pastoris

The transgenic yeast Pichia pastoris cultured for high level expression of rHSA was fed with Na_2SeO_3 during the induction phase in order to investigate incorporation of selenium into rHSA.After fermentation,the supernatant was processed by heat treatment,ultrafiltration,ion exchange chromatography and acetone precipitation and the molecular weight determined by Tricine-SDS-PAGE.Energy dispersive X-ray analysis(EDX) and atomic absorption spectroscopy(AAS) were then used to determine the selenium concentration.The results indicated that Na_2SeO_3 directly affects cell growth and rHSA yield.Furthermore,the experimental sample is found to contain 23.2% more selenium than the control(no addition of Na_2SeO_3) and the ratio of selenium to rHSA is 0.0069,which is about 35 times higher than the control.