Proceedings of the National Academy of Sciences · 1979 · 864 citations · 14 references
Life SciencesBiochemistryMolecular BiologyEnzymologyGene ExpressionProtein TranslationDiabetes Mellitus BiochemistryEnzyme ExpressionHormone SynthesisPlasmid BiologyProtein Expression EngineeringProtein SynthesisChainsEscherichia ColiEscherichia Coli Expression SystemsHuman InsulinInsulin BiochemistryInsulin BiosynthesisPrecursor Protein MaturationPurification
Synthetic genes for human insulin A and B chains were cloned separately in plasmid pBR322. The cloned synthetic genes were then fused to an Escherichia coli beta-galactosidase gene to provide efficient transcription and translation and a stable precursor protein. The insulin peptides were cleaved from beta-galactosidase, detected by radioimmunoassay, and purified. Complete purification of the A chain and partial purification of the B chain were achieved. These products were mixed, reduced, and reoxidized. The presence of insulin was detected by radioimmunoassay.
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