BIOL115 - Lecture 1

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  • Created by: Katherine
  • Created on: 13-05-16 09:13
What is serum albumin?
It is an a helix containing protein which transports a wide range of ligands and which has wide potential in drug delivery.
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What are the 3 major structural classes of globular protein?
A domain structures are made entirely of a helices. B domain structures are made entirely from B strands. AB domain structures are a mix of a helices and b strands. These are more complex in structure.
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Is the a helix stable?
No, only marginally so.
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As it is unstable, what happens to the a helix?
A helices tend to be packed pairwise in proteins, with their hydrophobic residues pointing towards the molecule's core.
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The creation of the hydrophobic region when the helices join together is ideal for what?
Ideal to put other hydrophobic molecules in, such as fatty acids.
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Why is the hydrphobic region good?
It stabilises the protein.
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Where is HSA found?
In the blood plasma. It is very abundant, more than 50% so it must be useful.
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What are the 2 major functions of HSA?
As a transporter of smaller, mostly hydrophobic molecules. As the major contributor of the osmotic swelling pressure of blood plasma.
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If you looked at the outcome of a classical electrophoresis of blood, what would you see?
Multiple peaks. a really wide range of things. It gives us insight into the wide range of molecules albumin transports.
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What is the structure of HSA?
It has an Mr of 66,500 so is a big protein. It has a pl of 5.67 and it almost entirely a helical in content. It consists of a single polypeptide chain containing 585 aas with 17 intra-chain disulphide bonds.
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What do the disulphide bond do?
They pull the molecule into a series of large and small double loops.
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Albumin is formed of how many small large loops?
3
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How might the smalle large loop system come about?
There may have been a mutation of a L, to LLL, which then mutated to LSL, which duplicated to get LSL,LSL,LSL.
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The AA sequence of albumin has an unusually high percentage of what?
Cysteines (Cys)
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How many Cys does HSA have?
35 out of 585 aas .
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Why are the cys important?
They're invovled in the transport role of Albumin. They help form a bond with another albumin, forming a dimer.
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Does Albumin contain many binding sites?
Yes,
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Cys 34 on the Albumin can bind which ions?
Cd, Au, Hg and Ag.
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The N terminal His-3 can bind which ones?
Cu(II), Ni (II)
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How is Cu (II) transported in the blood?
As a complex with albumin and free His. Albumin protects this from removal from the blood.
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What other drugs can be transported by Albumin?
Warfarin, Penicillin, AZT, Aspirin.
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Why is the albumin useful?
Because drugs competing for binding sites and small molecules may be excreted by the kidney into the urine. If it is carried by HSA, it is not cleared by the blood.
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What shape does HSA look like?
A heart shape. It has 3 domains.
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What happens when you add fatty acid to albumin?
It induces a change in the shape of the albumin.
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What happens to the fatty acid in the albumin?
The largely hydrophobic fatty acid is held within a region of 3 or 4 a helices created by the hydrophobic resides of HSA.
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What is the general structure of globular proteins, as in, where are the polar residues and where are the hydrophobic ones?
The polar residues are found on the external surface and the hydrophobic ones are buried in the interior.
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The Serum albumin ligands are..
Arachidonic acids
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What is hypoalbuminemia?
d
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How is a forest plot produced?
By meta analysis. You take studies that others have done and combine them all together.
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When people are low, what happens to their albumin?
It decreases. This is bed becuase Albumin is important in transporting a wide range of molecules.
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What can be done to fix this?
Ill people could also be given Albumin. It generally makes them get better faster.
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Is it better to treat a patient with a normal drug, or a drug coupled with Albumin?
Coupled
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What is serum Albumin?
A major a helix containing protein in blood plasma which serves and all purpose lorry, transporting smal hydrophobic molecules such as free fatty acids, hormones and drugs.
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Because of its ready availability, it is extensively used as what?
An Mr marker and as a blocking reagent in immuno-biochemistry
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Other cards in this set

Card 2

Front

What are the 3 major structural classes of globular protein?

Back

A domain structures are made entirely of a helices. B domain structures are made entirely from B strands. AB domain structures are a mix of a helices and b strands. These are more complex in structure.

Card 3

Front

Is the a helix stable?

Back

Preview of the front of card 3

Card 4

Front

As it is unstable, what happens to the a helix?

Back

Preview of the front of card 4

Card 5

Front

The creation of the hydrophobic region when the helices join together is ideal for what?

Back

Preview of the front of card 5
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