Genetic engineering has developed rapidly since its birth.

1972, Berger, head of biochemistry department at Stanford University, USA, artificially synthesized the DNA of two viruses, forming the first artificially recombinant DNA molecule, which is a pioneering work of genetic engineering.

1973, Cohen published a report that they connected the DNA of two plasmids of E.coli and sent them back to E.coli cells, and the DNA of the recombinant plasmid was replicated and expressed. This is the first time that genetic engineering has been completed.

From 65438 to 0976, somatostatin originally produced by human brain was produced by Escherichia coli in the United States, and the first practical genetic engineering was completed. Somatostatin is known to be a polypeptide chain containing 14 amino acids. After its structure is clear, its genetic structure-a 42-nucleotide DNA fragment can be deduced from the genetic code. Synthesize this DNA fragment and send it to Escherichia coli ... Since this research, scientists have mastered a new method of obtaining genes-artificial synthesis.

In a similar way, Americans produced insulin from Escherichia coli in 1978, which enabled insulin to be industrialized and brought good news to diabetic patients. The original source of insulin is extracted from bovine pancreas, and the yield is limited. Chemical synthesis of insulin is only scientific and has no practical value, because the cost is too high. At present, most of the insulin in the world pharmaceutical market is genetically modified.

Escherichia coli can also produce many substances, such as mouse growth hormone, human growth hormone, chicken egg albumin and human leukocyte interferon.

Biological methods: First cut the insulin gene, then transfer the insulin gene into human Escherichia coli, then create an environment conducive to the division of Escherichia coli, cultivate Escherichia coli on a large scale, and produce a large number of drugs for treating diabetes-insulin.

Gene preparation method: In the production process of genetically engineered human insulin, proinsulin is generally expressed first and then renaturated. The renaturated proinsulin was digested by enzyme to obtain active insulin. The renaturation efficiency of proinsulin is the key factor to determine the final yield. The molecular weight of correctly folded proinsulin is exactly the same as that of wrongly folded proinsulin, and the structure is very similar. RT-HPLC can be used to separate and detect proinsulin in renaturation solution. Sergeyev et al. established a method to detect proinsulin in renaturation solution by reversed-phase chromatography. If we want to further explain the structure of correctly folded proinsulin and wrongly folded proinsulin, we can hydrolyze it with protease V8, and then use RP-HPLC-MS as the skin atlas. Damn et al. digested proinsulin with Staphylococcus aureus protease V8, and then folded the recombinant proinsulin with R'FHPLC as the abdominal map combined with mass spectrometry.