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What are Amino Acids ?
The human body as we know it is a
very complex construction. Each and every organ of this body is
made of living cells. These organic cells are made up of huge
masses of protein molecules, which is the basic constituent of
all living cells. Amino acids are in fact the structural units
of these protein molecules.
There are large varieties of amino acids molecules that combine
with each other in a linear form to form chains of amino acid
molecules called the peptides. These peptides in turn combine
with other peptide molecules to form what we know as the protein
molecule. Now a question arises as to what controls the
formation and combination of these amino acids ? The answer to
this question lies in the genetic code. It is this genetic code
that dictates formation and combination of all amino acids. Each
and every protein, which forms an essential component of the
human body, has amino acids that follow this genetic code in
their structural formation.
What makes amino acids so very important for the human body is
the fact that human body cannot take proteins directly from the
food that they ingest. These proteins has to broken down into
amino acids so that they can form proteins as and when required
by the body. Also amino acids act as neurotransmitters, which
are used to transfer messages from one nerve cell to another.
This is due to the fact that amino acids are able to pass
through the blood brain barriers Amino acids are not limited to
human body or living cells alone. Infact there are hundreds of
different amino acids and astonishingly some of them have been
found in a meteorite also.
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Basic
structure
Most amino acids occur in two possible structures in the form of
two optical isomers, called D and L
L amino acids: The L amino acids represent the vast majority
of amino acids found in proteins. It represents the natural type
found in living plants and animal tissues. The L form is used in
human protein structures and is more compatible to human
biochemistry than the D form.
D amino acids : D amino acids are found in some proteins
produced by exotic sea-dwelling organisms, such as cone snails.
They are also abundant components of the proteoglycan cell walls
of bacteria. The D-isomer of aspartic acid is found in some
proteins as the result of a spontaneous post-translational
modification associated with protein aging or as the by-product
of enzymatic modification catalyzed by protein L-isoaspartyl
methyl transferase.
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Classification of amino acids is a
very difficult task. This is because of the fact that each and
every amino acid exists in a different protein environment, and
its role in the protein is generally far more complicated than
anything that could be defined by a set of groups. However amino
acids are classified into essential and the non-essential.
Essential amino acids as the name suggest these are the kind of
amino acids which are most essential for the human body and a
regular intake of these amino acids into our body is an absolute
must. These amino acids combine in several different ways in our
body to form more than thirty five thousand types of proteins
normally found in our bodies.
Some of the
standard essential amino acids include
Histidine promotes growth and repairs body tissues.
Isoleucine lack of these acids causes urinary problems.
Leucine essential for the maintenance of a sound immune system.
Lysine helps oxidation of fatty acids.
Matheonine facilitate fat and protein metabolism.
Phenylalanine produces several kinds of hormones including
melanin.
Threonine helps in break down of uric acids.
Trytophan induces sleep and mood changes.
Valine its a major requirement for the development of body
tissues.
Non essential amino acids non essential amino acids are those
amino acids which do not form proteins.
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Some of the
non essential amino acids include
Alanine plays a role in substrate recognition particularly
when it comes in contact with other non-reactive atoms such as
carbon.
Arginine has important role in cell division, the healing of
wounds, removing ammonia from the body, immune function, and the
release of hormones.
Asparagines Nervous system needs Asparagine to maintain the
equilibrium and also in amino acid transformation. It also plays
an important role in the synthesis of ammonia.
Asparatic acid plays a important role as general acids in
enzyme active centers, as well as in maintaining the solubility
and ionic character of protein.
Glutamic acid it is an essential component of folic acid which
is the building matter of vitamin c.
Glutamine helps In body muscle enhancement and also heals
damaged body cell. |
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Glycine acts as an inhibitory neuro
transmitter in the central nervous system.
Proline works as a catalyst in several organic reactions inside
the body. Proline also causes slight irritation to the tongue.
Serine When incorporated into the structure of enzymes, serine
often plays an important role in their catalytic function.
Taurine it is a constituent of bile and helps, among other things,
to regulate heartbeat, develop nerve tissue and stabilize cellular
membranes.
Properties of amino acids
Chemical properties properties of an amino acid is determined by
their side chain .The constituents of the side chain determines
whether the particular amino acids behave like an acid or a base.
Also the polarity of the side chain determines whether it is a
hydrophile or a hydrophobe. a hydrophile means it is easily
divisible in water or other liquid solvents while a hydrophobe is
actually exactly the opposite. The chemical properties of the amino
acids of proteins determine the biological activity of the protein.
Proteins not only catalyze all (or most) of the reactions in living
cells, they control virtually all cellular process.
Physical properties indicate a "salt-like" behavior because amino
acids are crystalline solids with relatively high melting points.
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Article Contributed By: Pinakjit
Kakati
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