Meaning of Amino Acids
What are amino acids:
Amino acids are monomers that form the basis of proteins that are vital for the proper functioning of our body.
Amino acids are composed of an amino group (NH2) which is a basic radical, and a carboxyl group (COOH) which is an acid group. The proteins of living beings are composed of the combination of 20 amino acids important for the body.
The union of 2 amino acids is due to a peptide bond between the carbon of the carboxyl group of the first amino acid and the nitrogen of the amino group of the second amino acid. This binding releases a water molecule and forms what is called a peptide.
The ligation of 2 or more peptides is called a polypeptide and, in turn, 1 or more polypeptide chains joined with a certain amino acid sequence and three-dimensional structure form a functional and mature protein. Depending on their structure, amino acids can be differentiated into L and D forms.
Structure of amino acids
Amino acids are generally made up of a carbon, a carboxyl group (COOH), an amino group (NH2), a hydrogen, and a functional group called the side chain or R group.
In this sense, the carboxyl group is attached to the amino group through the same carbon (central atom), called alpha carbon. This carbon is associated with a hydrogen and an R group, which will determine the chemical behavior of the amino acid.
At the biological level, the 20 amino acids from whose combinations proteins are formed therefore have different side chains. The simplest side chain is the one that constitutes the amino acid glycine, whose R group consists of only one molecule of hydrogen.
The sequence and type of amino acids necessary to synthesize proteins on ribosomes are determined by the information contained in the messenger RNA (mRNA or mRNA).
In this sense, amino acids are essential elements for the creation of polypeptide chains (future proteins) that ribosomes translate through the work between mRNA and transfer RNA (tRNA).
Types of amino acids
There are a large number of amino acids, approximately 250 amino acids that are not part of proteins and 20 amino acids that make up proteins, also known as alpha-amino acids.
The 20 amino acids that make up proteins are classified according to:
- the type of side chain or R group (hydrocarbons, neutral, acid or base),
- its chemical behavior (acidic, basic, polar or nonpolar), and
- whether or not it is synthesized by the human body (essential or nonessential).
However, beyond their classification, all amino acids are important for the human body and for maintaining good health.
Essential amino acids
Essential amino acids are those that the human body is unable to generate and are obtained through food. Of the 20 amino acids, 10 are the essential ones, being them: leucine, lysine, methionine, isoleucine, histidine, arginine, phenylalanine, threonine, valine and tryptophan.
Nonessential amino acids
There are 10 non-essential amino acids and they are those that the body can synthesize. They are of great importance because they generate the proteins necessary for the proper functioning of the body. The non-essential amino acids are: glycine, alanine, proline, serine, cysteine, glutamine, aspartic acid, glutamic acid, asparagine, and tyrosine.
The 20 amino acids
The 20 amino acids whose combinations constitute the proteins necessary for the proper biochemical functioning of our organisms are called alpha-amino acids.
Below are the 20 alpha-amino acids along with their classification, according to the type of side chain or R group (hydrocarbons, neutral, acid or base), their chemical behavior (acid, basic, polar or nonpolar) and if it is synthesized or not by the human body (essential or nonessential).
See also Proteins.
Function of amino acids
The amino acids fulfill diverse functions that are basic for the vital metabolic process of the organism, since they are the base of the proteins.
In this sense, amino acids share many of the functions of proteins, such as enzymatic and hormonal. Its most important functions include:
- Nutrient transport.
- Repair or growth of body tissues.
- Storage of nutrients such as water, proteins, minerals, vitamins, carbohydrates and fats.
- They can provide energy.
- Maintains the balance of acids in the body.
- Allows muscle contraction.
- It allows the proper development and functioning of the organs and glands.
- They intervene in the repair of tissues, skin and bones, as well as in the healing of wounds.