2. INSULIN
• A hormone produced by β-cells of the islets of Langerhans of pancreas.
• Play central role in carbohydrate and fat metabolism.
• Comprise of 51 amino acids with molecular weight of 5808
• It is formed by two chains- chain A and chain B linked together with a disulphide bond.
Chain A – 21 amino acid long while chain B is 30 amino acid long.
Chain A
Chain B Proinsulin
Chain C
s
s
s
s
s
s
s
s
Insulin
3. INSULIN- IMPORTANCE
Glucose Uptake by cells to perform
functions
Insulin
Glucose Cells cannot uptake
glucose
Diabetes- high blood
glucose levels
4. MANAGEMENT OF DIABETES BY THE
ADMINISTRATION OF INSULIN
Previously insulin was isolated from pancreas of the slaughtered animals, but there are
some limitations with this insulin
• Allergic reactions
Therefore insulin is produced by recombinant DNA technology
5. FORMATION OF INSULIN FROM PROINSULIN
Chain A
Chain B
Proinsulin
Chain C
s
s
s
s
s
s
s
s and
Post-translational
modifications
Insulin
Chain C
Removed from the
insulin
Chain A
Chain B
6. Protein- growth hormones, insulin,
E. coli
Bacterial
chromosome
Bacterial plasmid
Cell having gene of
insulin chain A
Gene for chain a of insulin is cut
out using restriction enzyme
Gene for insulin is inserted into bacterial plasmid
using DNA ligase enzyme
Recombinant plasmid-
Containing gene of interest
Plasmid put inside the bacterial cell
Recombinant bacterial cell
Cloned cells with gene of interest
Cultured cells cloned
having gene of interest
Chain A
Production of chain A of insulin
using recombinant DNA technology
Production of chain B of insulin using
recombinant DNA technology
E. Coli
Bacterial
chromosome
Bacterial plasmid
Cell having gene of
insulin chain B
Gene for chain a of insulin is cut
out using restriction enzyme
Gene for insulin is inserted into bacterial plasmid
using DNA ligase
Recombinant plasmid-
Containing gene of interest
Plasmid put inside the bacterial cell
Recombinant bacterial cell
Cloned cells with gene of interest
Cultured cells cloned
having gene of interest
Chain B
Both the chains are joined
by disulphide bonds
E. coli
E. coli
7. QUESTIONS RELATED TO INSULIN
• NEET-2008
• Human insulin is being commercially produced from a transgenic species of
• 1. E.coli
• 2. Mycobacterium
• 3. Rhizobium
• 4. Saccharomyces
8. AIPMT-2014
The first human hormone produced by recombinant DNA technology is
1. Insulin
2. Estrogen
3. Thyroxine
4. Progesterone
NEET-2020
Which of the following statements is not correct?
1. The proinsulin has an extra peptide called C-peptide
2. The functional insulin has A and B chains linked together by hydrogen bonds.
3. Genetically engineered insulin in E. coli.
4. In man, insulin is synthesized as proinsulin
