Biotechnology in pharmaceutical manufacturing

Amongst the earliest uses of biotechnology in pharmaceutical manufacturing is the use of recombinant DNA technology to modify Escherichia coli bacteria to produce human insulin, which was performed at Genentech in 1978.

[1] Prior to the development of this technique, insulin was extracted from the pancreas glands of cattle, pigs, and other farm animals.

The gene that was inserted into the plasmid was created by reverse transcription of the mRNA found in pituitary glands to complementary DNA.

HaeIII, a type of restriction enzyme which acts at restriction sites "in the 3' noncoding region"[5] and at the 23rd codon in complementary DNA for human growth hormone, was used to produce "a DNA fragment of 551 base pairs which includes coding sequences for amino acids 24–191 of HGH.

However, if the cDNA reverse transcribed from the mRNA for human growth hormone were inserted directly into the plasmid inserted into the Escherichia coli, the bacteria would translate regions of the gene that are not translated in humans, thereby producing a "pre-hormone containing an extra 26 amino acids"[5] which might be difficult to remove.

Thus, HIV infection posed a significant danger to patients with hemophilia who received human blood clotting factors: Most reports indicate that 60 to 80 percent of patients with hemophilia who were exposed to factor VIII concentrates between 1979 and 1984 are seropositive for HIV by [the] Western blot assay.

[7] This sequence of cDNA was used to find the remaining DNA sequences comprising the Factor IX gene by searching the DNA in the X chromosome:A genomic library from a human XXXX chromosome was prepared... and screen[ed] with a Factor IX cDNA probe.

[12] Recombinant DNA techniques have also been employed to create transgenic farm animals that can produce pharmaceutical products for use in humans.