Amino Acid
Introduction:
Amino Acid are the building blocks of proteins. This acids are organic compounds containing amine group (-NH2) and carboxyl functional groups (-COOH) along with a side chain (-R) specific for each amino acid. Amino acids play an important role in the process of gene expression (translation) working with the messenger RNA (mRNA). About 500 amino acids are known till now but only 20 amino acids participate in the protein formation. Amino acids as the building block of proteins form the second most abundant component of the human body that is about 50% of the dry weight of the body cell. In this article, the discussion will be all about the Amino Acid.
Types of amino acids:
There are total 20 amino acids forming the proteins.Depending upon varying features, amino acids are divided into 3 types;
- Essential amino acids
- Non-essential amino acids
- Conditionally essential amino acids
Essential amino acids:
Essential amino acids are those amino acids that are not produced by our body have to be supplied through diets. If they are not supplied through diet, their deficiency may occur that will lead to many complications. Essential amino acids are nine in number out of the 20 amino acids. These amino acids are:
- Leucine
- Isoleucine
- Lysine
- Threonine
- Methionine
- Phenylalanine
- Valine
- Tryptophan
- Histidine
Non-essential amino acids:
Non-essential amino acids are those that are not required through diet and can be prepared by the human body. Normally, their deficiency doesn’t occur as they are being replenished and prepared by the human’s own body. These amino acids are 11 in number. These include:
- Asparagine
- Alanine
- Arginine
- Aspartic acid
- Cysteine
- Glutamic acid
- Glutamine
- Proline
- Glycine
- Tyrosine
- Serine
Conditionally essential amino acids:
It is that type of amino acid in which a non-essential amino acid becomes essential depending on the diseased condition. This situation only occurs in a pathetic condition, it normally doesn’t occur.
For example:
In the disease of phenylketonuria, the enzyme phenylalanine hydroxylase converts the phenylalanine into tyrosine when the enzyme becomes dysfunction, it is not converter into tyrosine that is a non-essential amino acid but in this condition it becomes essential and has to be supplied through diet.
Another classification of amino acids:
Amino acids can be classified into some other types:
Glucogenic amino acids:
Glycogenic amino acids are those that are degraded to pyruvate or citric acid cycle intermediates e.g pyruvate, alpha-ketglutarate, Succinyl-CoA, Fumarate, Oxaloacetate, that can supply gluconeogenesis pathway.
For example:
- Alanine
- Cystosine
- Glycine
- Serine
- Threonine
- Tryptophan
- Asparagine
- Aspartate
- Glutamate
- Glutamin
- Histidine
- Proline
- Isoleucine
- Methionine
- valine
Ketogenic amino acids:
Ketogenic amino acids are those that are degraded to acetyl CoA or acetoacetyl CoA) - can contribute to synthesis of fatty acids or ketone bodies. Theses amino acid includes:
For example:
- Isoleucine
- Threonine
- Lysine
- Leucine
- Phenylalanine
- Tryptophan
- Some amino acids are both glucogenic and ketogenic.
Chemical reactions:
Peptide bond formation: Amino acids are join peptide bonds with the elimination of water molecule to form dipeptides, polypeptides and proteins. The peptide bond is former between two amino acids when the amino group of one amino acid reacts with the carboxyl group of another amino acid with the exclusion of the water molecule. The new bond that is former is of the “C-N” type and is known as peptide bond.
Role of Amino Acids:
In industry:
Amino acids are used in many industrial processes their main role is their use as additive to animal feed. Soybeans are rich in essential amino acids lysine, methionine etc are the main component of such feeds. The amino acids are add to these feeds to enhance the absorption of the minerals from the supplements that may be require to improve the health and production of these animals. In food industry glutamic acid is use as a flavor enhancer and aspartame is use as an artificial sweetener.
In human nutrition:
When the 20 amino acids are taken into the human body through diet, they are used to make the protein or code the message of DNA through reading the codons on mRNA. The required amounts of amino acids depend upon age and health of the individual. The deficiencies of amino acids have been linked to serious diseases.
Conclusion:
So, in a nutshell amino acids are essential components of proteins and play many important roles.
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