人胰岛素原类似物（B-Arg-Arg-A）基因的构建和表达

用聚合酶链反应（PCR）法将C肽为6个氨基酸残基的胰岛素原类似物基因删除突变成C肽仅为2个精氨酸残基的胰岛素原类似物（BArg-Arg-A）基因，即把pUC18BC'A改建为pUC18BR₂A。再将pUC18BR₂A与pJG105重组为表达质粒pJG107，使B-Arg-Arg-A与pJG105编码的一种多肽构成融合蛋白在大肠杆菌体系中表达。融合蛋白占细菌蛋白总量的58%。表达产物具有人胰岛素放射免疫活性。

Construction and Expression of the Gene for Human Proinsulin Analog(B-Arg-Arg-A)

By means of deletion mutagenesis by polymerase chain reactio (PCR), a plasmid, pUC19BR2A, was constructed which contained the codons of ananalog(B-Arg-Arg-A) of human proinsulin in which the normal35-amino acid connecting peptide was replaced by dipeptide(Arg-Arg). An expression plasmid with PRPL promoter, pJG107, was constructedwhich encoded a fusion protein consisting of B-Arg-Arg-A and a polypeptide of 72 amino acid. Expressed in Eschericbia coli, the fusion protein with insulin immunoreactive activity measured by radioimmunoassay accounted for 58% of total bacterial protein.