Explain the steps involved in the production of genetically engineered insulin. Whay is the insulin thus produce preferred over the one produced from qnimal source.
Answers
Insulin:
Insulin is secreted by islets of langerhans of pancreas.It consists of two polypeptide chains,Chain A (21 amino acids) and chain B (30 amino acids).
The precursor of insulin is proinsulin which contains chain A, chain B and chain C (35 amino acid).
Procedure:
The mRNA for this proinsulin is isolated from rats,
cDNA is synthesized from this mRNA
This cDNA is integrated with the plasmid of E.coli near the beta-galactosidase gene.
The recombinant plasmid is then transfected into E.coli.
The E.coli is the cultured.The cDNA is expressed to produce fused beta-galactosidase chain A and beta-galactosidase chain B.
The chains are them separated from beta-galactosidase.
The chain A and chain B were joined invitro by treating them with sodium disulphonate and sodium sulphite.
This insulin produced is called 'Humulin' .