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A-Z Guide to Amino Acid

Last updated date: 19th Feb 2024
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Introduction to Amino Acid Formula

The building blocks of proteins are amino acids. They are called so due to the reason that the enzymatic digestion of the proteins leads to the amino acids formation. The French chemists have discovered the first amino acid by isolating a compound from asparagus. The first amino acid is titled “Asparagine”. More than 500 naturally occurring amino acids were found. Among these amino acids, only 20 were found in the genetic codes.

In this article, let us learn about amino acid classification, amino acid formula, amino acid molecular formula, structure, and properties.

What are Amino Acids?

Amino acids are the monomers of the polypeptide chain or proteins. These are made up of carbon chain, amino group and acetate group. Amino acids connect each other to form small chains of polymers called peptides and larger chains are called polypeptides or proteins. Non-proteinogenic amino acids are formed as a result of post-translational modifications.

General Formula of Amino Acid

Amino Acid formula, is also known as the Nitrate of potash formula or Saltpeter formula. This organic compound is made up of functional groups namely amine and carboxyl. Along with these functional groups, it has a side chain that is specific to each amino acid. The major elements that are present in the functional groups include carbon, nitrogen, hydrogen, and oxygen.

The general formula of amino acid is given as R-CH(NH2)-COOH. Here -NH2 represents the basic amino group, -COOH is the acidic carboxyl group. R represents the organic side chain that is found to be unique in each and every amino acid.

In every molecule of amino acid, the carbon atom (⍺-carbon) is placed at the center to which both the carboxyl group and hydrogen atom are placed closer.

Amino Acid Structural Formula

Amino Acid Classification

Amino acids are classified into three types depending on their essentiality:

  • Essential Amino Acids: Essential amino acids belong to a group of amino acids that cannot be created by the human body. As a result of this, they must be obtained through food. There are nine essential amino acids namely lysine, isoleucine, histidine, leucine, methionine, tryptophan, phenylalanine, threonine, and valine.

  • Non-Essential Amino Acids: Non-essential amino acids belong to the group of amino acids that our bodies can produce. Some of the non-essential amino acids are alanine, cysteine, arginine, asparagine, aspartic acid, glutamine, glutamic acid, glycine, serine, proline, and tyrosine.

  • Conditional Amino Acids: Conditional amino acids are usually not essential, except in times of illness and stress. Conditional amino acids include arginine, cysteine, glutamine, tyrosine, glycine, ornithine, proline, and serine.

Uses of Amino Acid

1. In industry:

  • Several amino acids and their derivatives are used as flavour enhancers in many dishes. For example, monosodium glutamate is a derivative of glutamic acid.

  • Used as preservatives in packaged foods, the commonly used amino acid is cysteine.

  • Many of the plant-based products lack certain amino acids thus certain amino acids are used to increase the nutritional value.

  • Some of the amino acids are used as a precursor for certain kinds of chemicals.

2. In Humans:

  • For the good growth of an individual, there is a need for proteins, thus amino acids help in the healthy growth of an individual.

  • Helps to repair the body tissue.

  • Amino acids are required to perform various functions in the body.

3. In the Field of Medicine:

  • The amino acid chemical structure is used in the treatment of imbalances occurring due to brain metabolism and neurotransmission.

  • Used to improve gastrointestinal health, cardiovascular health, and immune system.

  • To prevent the GI toxicity that is induced due to chemotherapy.

Production of Amino Acids

The amino acids can be produced by various methods namely,

  • Chemical Synthesis: Amino acids can be synthesised chemically. In the chemical synthesis of amino acids, certain methods are extracted from natural sources, enzymatic catalysis, or fermentation. Chemical synthesis is used for the mass production of specific amino acids in industry. But there is a major drawback of this technique is, it can produce two forms of amino acids called enantiomers. They should be separated before they are released to use.

  • Fermentation: Fermentation is currently used only for the synthesis of lysine and glutamic acid. For industrial production of amino acids trains of certain mutant bacteria are needed, but they are difficult to produce.

  • Biosynthesis: In plants, nitrogen can be assimilated first to form organic compounds in the form of glutamate in the mitochondrion. For another type of amino acids, plants use transaminases in order to move the amino group. Non-standard amino acids are usually made by modifying the standard amino acids.

Difference Between Essential and Non-Essential Amino Acids

Essential Amino Acids

Non-Essential Amino Acids

These cannot be made inside the body therefore, these are included through our diet or food supplements.

These can be produced by our body or are always available.

Nine out of 20 essential amino acids are known.

Eleven out of the 20 nonessential amino acids known.

They help in the building and repairing of muscle tissues. They can act as precursor molecules for the formation of neurotransmitters in the brain.

They are very helpful in the removal of toxins, promote brain function, and synthesise RBC and WBC in our bodies.

Example: Lysine, histidine…

Example: Alanine, glutamine…


Amino acids are the monomers of the polypeptide chain or proteins. These are made up of carbon chain, amino group and acetate group. Amino acids connect each other to form small chains of polymers called peptides and larger chains are called polypeptides or proteins. The general formula of amino acid is R-CH(NH2)-COOH. Three types of amino acids are present: essential amino acid and non essential amino acid and conditional amino acid.

FAQs on A-Z Guide to Amino Acid

1. Mention the uses of amino acids in the human body.

Different amino acids are required for the functioning of a healthy human body:

  • Phenylalanine acts as a precursor for brain chemicals like epinephrine, dopamine, and norepinephrine. These chemicals are brain messengers.

  • Valine helps in the healthy growth of muscles, regeneration of the tissues, and is required for the synthesis of energy.

  • Threonine provides structure to the skin and connective tissue. It also helps to prevent excessive bleeding by the formation of blood clots. It also helps in the metabolism of fat and boosts the functioning of the immune system.

  • Tryptophan helps in the synthesis of serotonin, a neurotransmitter thus maintaining the nitrogen levels in the body. Serotonin regulates good mood, appetite, and sleep.

  • Methionine helps in the metabolism, tissue growth, and detoxification of the body. It is also involved in the absorption of essential minerals, such as zinc and selenium.

  • Leucine helps in the synthesis of muscle growth and repair, heals wounds, regulates blood sugar levels, and synthesises growth hormones.

  • Isoleucine helps in the metabolism of muscles, boosts immune function, synthesises haemoglobin, and regulates energy.

  • Lysine helps in the synthesis of enzymes and hormones. It absorbs the calcium content from food, produces energy, and improves immune function.

  • Histidine is involved in the synthesis of the neurotransmitter, histamine. It helps in the digestion and regulation of sleep cycles.

2. Write down amino acid properties.

The different properties of amino acids include:

Amino Acid Physical Properties: 

They show optical isomerism as they are absorbed in the ultraviolet region. All the amino acids contain two ionizable groups namely a carboxyl group and an amino group.

Amino Acid Chemical Properties: 

  • The chemical properties of amino acids are observed due to the presence of the carboxyl group, the amino group, and the radical R. 

  • They can form salts and undergo the process of decarboxylation in the presence of the carboxyl group. 

  • Formaldehyde reacts with the NH2 of amino acids at room temperature and the neutral pH to form hydroxymethyl derivatives. 

3. What is the aminoacid molecular formula?

The molecular formula of amino acid is given as R - CH(NH2) - COOH.