AMINO ACIDS
Chirality of amino
acids/cis-trans
This image shows the chirality of amino acids/cis-trans versions of the amino acids alanine and proline.
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Alanine
Alanine is coded for in the genome and is therefore a non-essential amino acid, which means that it can be produced by the
body and doesn’t need to come from the food we eat. Alanine is one of the simplest amino acids in terms of its structure
and features in the production of a variety of proteins. The main role of alanine is in the metabolism of glucose.
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Arginine
Arginine is coded for in the genome, but is considered a semi-essential amino acid. This means the body normally makes
enough of it, but additional supplementation is sometimes needed. Arginine is important in the removal of ammonia from
the body and in the production of urea. It may also have roles in wound healing and cell division.
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Asparagine
Asparagine is coded for in the genome and therefore is a non-essential amino acid, which means that it can
be produced by the body and doesn’t need to come from the food we eat. Asparagine plays a part in the
biosynthesis of other proteins and is important for correct function of the brain and nervous system.
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Aspartic acid
Aspartic acid is coded for in the genome and therefore is a non-essential amino acid, which means that it can be produced
by the body and doesn’t need to come from the food we eat. It plays an important part in the citric acid (or ‘Krebs’) cycle in
energy production and can stimulate NMDA receptors. It is therefore thought to help concentration and brain function.
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Cysteine
Cysteine is coded for in the genome and is therefore, a non-essential amino acid, which means that it can be produced by
the body and doesn’t need to come from the food we eat. However, it may be required in the diet of young infants, the
elderly and individuals with metabolic diseases. Cysteine helps protect cells from free radicals and plays a vital part in the
detoxification function of the liver. Cysteine is an essential amino acid in other animals. For example, it’s required by sheep
for wool production and must be ingested and assimilated from grass.
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Glutamic acid
Glutamic acid is coded for in the genome and is therefore a non-essential amino acid, which means that it can be produced
by the body and doesn’t need to come from the food we eat. Glutamic acid is a key molecule in cellular metabolism,
particularly in the metabolism of sugars and fats. Glutamates (salts of glutamic acid) are a very important and abundant
neurotransmitter. They are also important for brain function. However, some glutamates, such as monosodium glutamate
(MSG), have prompted health concerns.
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Glutamine
Glutamine is the most abundant non-essential amino acid, which means that it can be produced by the body
and doesn’t need to come from the food we eat. Glutamine plays a part in ammonia removal and is
important in the function of the immune system. It can become a conditional essential amino acid after
illness or injury when the body requires higher levels than it can make.
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Glycine
Glycine is coded for in the genome and is therefore a non-essential amino acid, which means that it can be
produced by the body and doesn’t need to come from the food we eat. Glycine is normally only required in
small amounts with the exception of collagen, which is composed of a high percentage of glycine molecules.
It’s also used to produce many naturally occurring products and as an additive in a number of products.
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Hystidine
Hystidine is an essential amino acid in children and is required as part of our diet. However, as humans grow
they begin to synthesise it, and it becomes a non-essential amino acid, meaning the body can produce its
own supply and it doesn’t need to come from the food we eat. Hystidine is commonly involved in enzymatic
reactions. It’s also required for histamine production, which acts to stimulate the inflammatory response.
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Isoleucine
Isoleucine is an essential amino acid, which means it cannot be made by the body and needs to be obtained
through diet. Isoleucine is an isoform of leucine and is required for the formation of haemoglobin. It is also
commonly involved in muscle recovery after exercise.
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Leucine
Leucine is an essential amino acid, which means it cannot be made by the body and needs to be obtained
through diet. Leucine is important for the production of haemoglobin and is required in muscle, adipose and
liver tissue. It’s important in preventing muscle degradation.
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Lysine
Lysine is an essential amino acid, which means it cannot be made by the body and needs to be obtained
through diet. Lysine plays a part in calcium absorptions, and derivatives of lysine are required for the
production of elastin and collagen.
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Methionine
Methionine is an essential amino acid, which means it cannot be made by the body and needs to be
obtained through diet. It’s essential in methylation, a process where a methyl group is added to compounds.
It’s also involved in the breakdown of fat and the sulphur assists in the removal of free radicals.
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Phenylalanine
Phenylalanine is an essential amino acid, which means it cannot be made by the body and needs to be
obtained through diet. It’s commonly found in breast milk, and it is important in the production of various
brain chemicals and has an impact on mood, energy, alertness and memory.
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Proline
Proline is one of the 20 amino acids coded for in the genome and produced by the body making it a nonessential amino acid. Proline is also synthesised from glutamic acid. It’s important for development of skin
and connective tissue.
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Serine
Serine is a non-essential amino acid, which means that it can be produced by the body and doesn’t need to
come from the food we eat. Serine is important in metabolism and is the precursor to many other amino
acids and metabolites.
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Threonine
Threonine is an essential amino acid, which means it cannot be made by the body and needs to be obtained
through diet. Good sources of threonine are found in meat, dairy and eggs. It is a precursor for some other
amino acids such as glycine and serine.
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Tryptophan
Tryptophan is an essential amino acid, which means it cannot be made by the body and needs to be
obtained through diet. It’s thought to be required in the production of various neurotransmitters, including
serotonin, and it may help reduce anxiety and aid sleep.
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Tyrosine
Tyrosine is one of the 20 amino acids coded for by the genome, so it is a non-essential amino acid, which
means that it can be produced by the body and doesn’t need to come from the food we eat. It can be
synthesised from phenylalanine and plays a part in signal transduction, acting as a receiver of phosphate
groups. It’s also a precursor to the pigment melanin.
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Valine
Valine is an essential amino acid, which means it cannot be made by the body and needs to be obtained
through diet. In sickle cell disease, valine is present instead of glutamic acid in haemoglobin, and as a result
the protein doesn't fold correctly making it less efficient at carrying oxygen.
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