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Click here for Amino Acid Products Next to water, protein is the most abundant
substance in the human body. Complex mega-molecules of protein
are the structural building blocks of tissue. The thousands of
different proteins in our bodies are composed of 20 molecules
called amino acids. In the last 20 years, research has shown the
benefits of amino acid supplementation to such diverse areas of
human biochemistry as metabolism, enzyme and neurotransmitter
production and antioxidant protection. Source Naturals utilizes
the latest-breaking research to bring you a highly comprehensive
line of amino acid
supplements. ---------------------------------------------

Amino Acids

provides the instruction manual for life, RNA reads the manual
and the genetic information is expressed by proteins. Proteins
are the most abundant macromolecules in living cells
constituting 50% or more of their dry weight. They create the
structure of our cells and tissues, and play an essential role
in virtually all of the biochemical events that animate those
tissues. The term "protein" refers to a set of
macromolecules that encompasses an extensive variety of
structure and function&endash;from helical rods with the tensile
strength of steel to elastic sheets to huge molecular machines
with hinged jaws that snap closed to hold other molecules in
place. Amazingly, all proteins, in their remarkable variety, are
built out of a set of 20 simple molecules called amino
acids. Amino acids are one of the four types of small
molecules out of which all life is constructed. The other three
are: palmitic acid (see "Essential Fatty Acids," page #),
adenine and glucose. All amino acids share a common chemical
"backbone" which consists of an a -carbon atom to which four
substituent groups are bonded: a nitrogen-containing amino group
(H2N), a carboxyl group (COOH), a hydrogen atom and an "R"
group. The "R" group or side chain (figure #) varies in electric
charge, size, structure and solubility in water, giving each
amino acid its distinct chemical properties. Since all amino
acids (except glycine) contain at least one asymmetrical carbon
atom, each one exists in at least two forms: the l form and its
mirror image or stereoisomer, the d form. While both forms are
found in biological systems, only the l form is present in
proteins. Amino acids are linked together like beads on a
string to form proteins, sometimes called peptides because of
the peptide bonds that link the amino acids together. They range
in size from simple two-amino-acid dipeptides to polypeptides
which contain more than 1800 connected amino acids. The chemical
backbone of the amino acids and their sequence constitutes the
primary structure of a protein. Polypeptide chains then fold
into specific 2 and 3-dimensional configurations that are unique
for each type of protein. The pattern of folds, along with the
chemical nature of the amino acid side chains contained in it,
give a protein its characteristic biological activity. For
example, the connective tissue proteins collagen and elastin
give structure to cellular organelles and tissues, while
proteins called enzymes catalyze and facilitate metabolic
chemical reactions. Nine of the 20 amino acids involved
in protein synthesis are considered "essential";they cannot be
synthesized by the body and must be obtained from food sources.
The term "non-essential" is sometimes used to classify the other
eleven amino acids. However, this word is perhaps a misnomer; a
better term might be synthesizable. These amino acids are just
as vital to human metabolism as the "essential" amino acids; so
vital that the body can synthesize them. They are, however, more
available, more versatile, and more interchangeable. When
the presence or absence of a particular amino acid will
determine whether a protein can be created or not, that amino
acid is called a rate-limiting factor for that protein. For
example, the tripeptide glutathione, a compound that forms an
important part of the body's protective mechanisms, is made of
the amino acids glutamic acid, glycine and cysteine. Glutamic
acid and glycine tend to be plentiful in the diet, and can be
easily interconverted. Cysteine is the rate-limiting factor for
glutathione; the amount of cysteine in the diet will determine
the amount of glutathione that can be manufactured by the
body. Amino acids have a special role to play in brain
nutrition, because all neurotransmitters are derived from amino
acids or related compounds such as choline. Brain
neurotransmitters, specifically, are biochemical keys to the
workings of the mind. They are substances that perform chemical
transmission of nerve impulses between neurons or between
neurons and other cell types such as muscle. They work in the
following way: an electric current (or action potential) travels
down the length of a neuron, or nerve cell, until it reaches the
synapse - a narrow gap between two cells. The incoming nerve
impulse triggers the release of neurotransmitter (NT) molecules,
which diffuse across the synaptic gap. The neurotransmitter
molecules bind with receptor proteins embedded in the membrane
of the post synaptic neuron and activate a physiological
response. Excitatory neurotransmitters propagate a new action
potential while inhibitory NT's inhibit the development of new
action potentials. The amino acid precursors of
neurotransmitters are able to cross the blood-brain barrier, a
structural feature of brain anatomy that prevents many
substances from contacting brain tissue. Thus, it is possible to
influence brain metabolism (and therefore emotional states)
through the mechanism of neurotransmitter synthesis. The
enhancement of neurotransmitter production is one of the most
exciting advancements to occur in the field of nutrition in
modern times. A major portion of the amino acid
requirement in humans is derived from the proteins in food.
Successive proteolytic enzymes attack the peptide bonds,
cleaving one amino acid at a time from the polypeptide chain.
Ultimately, free amino acids as well as small peptides
(especially dipeptides) are absorbed through the mucosal cells
of the small intestine. The small peptides are then further
hydrolyzed so that only free amino acids enter the liver and
portal vein. This sounds like a fairly straightforward process.
However, the presence of a particular amino acid profile in a
certain food does not guarantee the assimilation of those amino
acids when the food is ingested. There are three types of amino
acids: acidic, basic and neutral; each of these classes has a
different transport mediator. Therefore, there is competition
for the carrier between any two amino acids in a certain class,
both in the digestive tract and at the blood-brain barrier.
Thus, the isolation of "free-form" amino acids is an important
aid to nutritional engineering. In many cases, the consumption
of high potencies of a particular amino acid allows that
nutrient to overwhelm the competition for absorption. The
resulting increase in blood and tissue levels will yield the
benefits conferred by that nutrient. The isolation of
free-form amino acids is an important advancement in the field
of nutrition science. Amino acid supplements offer a broad range
of choices to complement your nutritional program.