Transcript - The Wonderful Hormone - INSULIN - UCO

- The Wonderful Hormone INSULIN
By Jeremy Wynn
Cell Physiology
Insulin

What is Insulin
–
–
–

Where does it come from?
What is the big deal about it?
What is the actual structure?
Problems with Insulin
–
–
What are the classifications of diabetes?
What is done about it?
What the big deal about Insulin??

Insulin is a naturally occurring hormone,
produced in the Islets of Langerhans of the
pancreas, that regulates the metabolism of
carbohydrates, fats, and starches in the body.

Insulin is required by the cells of the body in
order for them to remove and use glucose from
the blood.

Insulin stimulates the formation of glycogen in
the muscles and in the liver. Insulin also
controls the uptake of valine, leucine, and
isoleucine by the muscles, which in turn helps to
increase the synthesis of muscle proteins.
The Actual Structure

Structure
– A single insulin molecule consists of 2
polypeptide chains, A (21 amino acids)
and B (30 amino acids)
– The chains being held together by two
disulfide bonds. A third disulfide bond
is present within the A chain.
- Structure of Human Insulin -
Other Important Facts about
the Structure

Insulin molecules have a tendency to
form dimers in solution due to hydrogenbonding between the C-termini of B
chains.

Additionally, in the presence of zinc ions,
insulin dimers associate into hexamers.
The Insulin Dimer and Hexamer
What to do about the formation of
Dimers and Hexamers?

The Lys and Pro are reversed.
– This minimizes the tendency to form dimers
and hexamers
Problems associated with Insulin

Type I AND II Diabetes Mellitus
– Type I, which is genetic, is caused by an
autoimmune response of the white blood cells to
destroy the beta cells of the pancreas
• Take insulin injections
– Type II which is more common is usually caused by
too high an insulin concentration in the blood
stream.
• This is caused by the target cells' hyporesponsiveness
to insulin.
• Placed on an exercise program
Clinical Production of Insulin

Insulin was first synthesized in 1979 in E.
coli cells through the use of recombinant
DNA techniques.

In 1982, synthesized insulin produced by
genetically altered bacteria was approved
for use with insulin dependent patient
– This form of insulin is an exact match to that
which is made in the body
Summary




Insulin is a hormone produced by the pancreas that regulates blood
glucose levels and
– stimulates glucose transport
– stimulates amino acid transport
– Increases glycogen synthase activity
– increases the rate of general protein synthesis
Insulin consists of an A chain that has 21 a.a. and a B chain that has 30
a.a.
– With 3 disulfide bonds
Diabetes Mellitus
– Type I – Low level, genetic, autoimmune disease
– Type II – High levels, target cells not responding, increase adipose
tissue
Insulin can be manufactured by
– Pig Insulin
– Insulin made by E. Coli by recombinant DNA techniques