This document summarizes a lecture on biopharmaceuticals given by Dr. Okoth. It discusses insulin, including its structure, production in the pancreas, mode of action, and receptors. Insulin regulates blood glucose levels and is required for normal body function. Porcine and bovine insulin resemble human insulin in structure. The lecture also describes how recombinant DNA technology is used to produce human insulin through insertion of the human insulin gene into bacterial cells like E. coli, which are then cultured to produce insulin.

1. BIOPHARMACEUTICALS
SBT 426
LECTURED BY: DR. OKOTH patrick, PhD.

2. GROUP MEMBERS
NAME REG. NUMBER
GIBSON MOKAYA BTE/0065/14
ONYANGO CHARLES BTE/0047/14
GEOFFREY NYATINDO BTE/0046/14
KIPROTICH KELVIN BTE/0036/14
DOMINIC KIGEN BTE/0032/14
BENSON KIRIINYA BTE/0028/14
VANESSA ADHIAMBO BTE/0056/14

3. INSULIN AS A HORMONE
 Insulin is a hormone that regulates the amount of glucose (sugar) in the blood and is
required for the body to function normally.
 In other words, insulin is a hormone that is important for metabolism and utilization
of energy from the ingested nutrients, especially glucose.
 Insulin's structure varies slightly between species of animals, both porcine(from pigs)
and bovine(cows) insulin are similar to human insulin but porcine insulin resembles
human insulin more closely

4. GENERAL STRUCTURE OF INSULIN

5. INSULIN PRODUCTION IN THE PANCREAS.
 Insulin is produced by cells in the pancreas, called the islets of
Langerhans.
 Insulin hormone is produced by beta cells in the pancreas.
 The structure of insulin differs slightly between species.
 The C terminal amino acid of B chain is alanine in porcine and
threonine in human insulin.

6.  For sometimes now, insulin derived from animal
pancreas have been used to treat diabetes. However
there are two problems associated by using such
insulin;
 Immunological incompatibility- causes
immunogenic response in some diabetic patients,
supply of pancreas fluctuates with meat trade.

7. INSULIN MODE OF ACTION.
 It causes the cells in the liver, muscles, and fat tissue to take up
glucose from blood and convert it to glycogen that can be stored in
the liver and muscle.
 Insulin also prevents the utilization of fats as an energy source. In
absence of insulin or in conditions where insulin is low, glucose is
not taken up by body cells, and the body begins to use fats as an
energy source.
 Insulin also controls other body systems and regulates the amino
acid uptake by body cells.
 It has several other anabolic effects throughout the body as well.

8. INSULIN RECEPTORS
 An insulin receptor belongs to a family of receptor tyrosine kinases, which phosphorylates their
substrates protein on tyrosine residues.
 The receptor comprises of two subunits: the extracellular alpha subunit and the transmembrane
better subunit.
 The functional receptor exists as a dimer.
 The alpha subunit contains the ligand binding sites, as it the only subunit identified by affinity
labelling protocols.
 The beta subunit is involved in intracellular signaling.

10. SIGNAL TRANSDUCTION
 While insulin interacts with the receptors , dimerization of the receptors takes place, due to this,
the cytoplasmic domains of the receptor come close together facilitating phosphorylation and
triggering the signal transduction pathway.
 In short, insulin’s interactions with its cell surface receptors triggers both metabolic and mutagenic
cellular responses.
 In order to do this, insulin two kinds of pathways:
i. Ras-dependent pathway
ii. Ras-independent pathway

12. PRODUCTION OF INSULIN THROUGH
RECOMBINANT DNA TECHNOLOGY
 Human insulin is produced in E-coli by inserting gene of insulin with suitable vector. Product is
known as humulin, was first produced by Ely Lilly by recombinant DNA technology.
 The process involves;
a. Preparing
The human gene is isolated. The mRNA is taken from the cells of islets of Langerhans.
Messenger RNA is a molecule of RNA that encodes a chemical "blueprint” for a protein product. The
isolated gene contains the code of the human DNA for the production of insulin.
The plasmid DNA of the bacterium cell is taken out of the cell. E-coli bacteria is widely used in
producing insulin but yeast may also be used.

14. b. Restriction
The plasmid DNA of the bacteria is cut out producing plasmid ring
which is an empty segment of the DNA. A restriction enzyme is an
enzyme that cuts DNA at restriction sites. A segment of DNA known as
sticky ends are obtained
c. Joining
With the plasmid ring open, the gene obtained from human cell that
contains the code of protein responsible for the production of insulin is
inserted into the plasmid ring and the ring us closed. The human insulin
gene is now combined with the bacterial DNA plasmid

15. d. Inserting
the resulting DNA is inserted back into the bacteria
e. Culturing of the resulting bacteria
The cells need nutrients in order to divide and live
While they live, the bacterial cell processes turn on the gene for
human insulin and the insulin is produced in the cell.
When the bacterial cells reproduced by dividing, the human
insulin gene is also reproduced in the newly created cells

18. HAVE A PRODUCTIVE
SEMESTER,