Albumin is a large
abundant protein in our blood. When blood is collected in a tube and left
to stand, the red cells, containing hemoglobin will sink to the bottom.
The liquid on top is called serum or plasma. Albumin gives it the
yellowish color. Serum also contains various components important for our
overall health. The white blood cells and platelets will be in
between these two layers - in the interphase.
We should all know about
a blood test for Albumin (by my health care provider):
Normal amounts of Albumin: 3.3 - 4.8 g/dL. Albumin is a protein that is made in the liver
and released into the blood. It helps keep the blood from leaking out of blood
vessels. Albumin also helps carry some medicines and other substances through
the blood and is important for tissue growth and healing.
Chemistry of albumin: Human serum albumin - HSA is made of
609 amino acids. (Yes six hundred and
nine amino acids!) Bovine serum albumin
- BSA has a very similar chemistry with small differences in amino acid
sequence. Here is the 3D structure of
both proteins pointing out this specific difference:
Human and Bovine Serum Albumin:
The similar structure of albumin in various organisms can be
followed from lower organisms to higher ones.
This is the scientific base of evolution. In comparative genetics the scientists can
compare the amino acid sequence of mouse, rat, dog, bovine and human and show
the homology. There is a higher fit or
homology between human and bovine, than between human and mouse.
Albumins belong to a group of proteins described as globular
proteins, referring to their spherical shape.
This shape makes them soluble in water, so their location in the cell is
in the aqueous, or water environment.
Some proteins are membrane proteins which means they are not soluble in
water and will be attached to the cell wall or membrane.
An important aspect of biochemistry of proteins is transport
of nutrients or drugs depending on their solubility in water. Albumin has an important role as a “universal”
solvent. Here you can see how Albumin
can attach various molecules as fatty acids which are lipids, or calcium which
is a small ion, and transfer them through the blood to their destination in the
body.
Albumin attached to various drugs and nutrients:
In this post on Albumin I have introduced the principles of
soluble and membrane proteins and some basis of evolution. I hope more people would study these topics and learn to appreciate our amazing complex biology.
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