Page 32 - The Miracle of Protein

30 THE MIRACLE OF PROTEIN

The Order in Amino Acids
Proteins consist of molecules known as amino acids. Al-

though smaller than proteins, amino acids still exhibit rather
complex structures. The atoms comprising amino acids fall into
three separate categories: the amino group, the carboxyl group

and the side chain or radical group.
The amino and carboxyl groups are the same in all amino
acids. The only thing that differentiates one amino acid from

the other ones is the side chain group that binds to the molecule
from one side. These different side chain groups in every amino
acid give them their distinct features.

In the same way that various materials are used to produce
a machine, there must be certain components with different

properties in the protein "machines" if they are to perform their
exceedingly complex functions in the body. In the side chain
amino acids, the form, number and sequence of atoms, their

electrical charges and diverse hydrogen binding capacities all
endow the amino acids with considerable variety. And from this
widely diverse material are produced a great variety of proteins.

For instance, whether amino acids can dissolve in water or not
depends on if the side chain groups have a positive (+) or nega-
tive (-) electrical charge, or no charge at all.

Amino acids with distinct properties line up alongside one
another in different sequences, permitting the proteins that re-
sult to perform an astonishing range of functions in the body.

However, the amino acids present in living things are very spe-
cial. Although more than 200 types of amino acids can be used
in living beings, only 20 of them are used in protein synthesis.