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
Conclusion:
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. What are amino acids and what is their general structure?
Amino acids are organic molecules that serve as the fundamental building blocks of proteins. They are characterised by having both an amino group (-NH₂) and a carboxyl group (-COOH) attached to the same carbon atom, known as the alpha-carbon. The general formula is R-CH(NH₂)COOH, where the 'R' group is a variable side chain that is unique to each amino acid and determines its specific properties.
2. How are amino acids classified based on the nature of their side chain?
Based on the nature of the 'R' group, amino acids are classified as per the CBSE syllabus into three main types:
- Neutral Amino Acids: The side chain is neutral and contains no extra acidic or basic functional groups (e.g., Glycine, Alanine, Valine).
- Acidic Amino Acids: The side chain contains an additional carboxyl group, making the overall molecule acidic (e.g., Aspartic acid, Glutamic acid).
- Basic Amino Acids: The side chain contains an additional amino group, making the overall molecule basic (e.g., Lysine, Arginine).
3. What is the difference between essential and non-essential amino acids?
The key difference between these two types of amino acids lies in their source for the human body:
- Essential amino acids cannot be synthesised by the body and must be obtained from your diet. There are nine essential amino acids, including lysine, valine, and tryptophan, which are vital for functions like growth and repair.
- Non-essential amino acids can be produced by the human body from other compounds, so they are not a mandatory component of the diet. Examples include alanine, glycine, and glutamic acid.
4. Why are amino acids described as amphoteric? Explain the concept of a zwitterion.
Amino acids are called amphoteric because they contain both an acidic group (the carboxyl group, -COOH) and a basic group (the amino group, -NH₂). This dual nature allows them to act as both an acid and a base. In neutral aqueous solutions, the proton from the carboxyl group transfers to the amino group, forming a dipolar ion called a zwitterion. A zwitterion has both a positive charge (-NH₃⁺) and a negative charge (-COO⁻) but is electrically neutral overall, a key property discussed in the NCERT curriculum.
5. How do individual amino acids join together to form a protein?
Amino acids link together through a specific type of covalent bond known as a peptide bond. This bond is formed through a dehydration reaction where the carboxyl group (-COOH) of one amino acid reacts with the amino group (-NH₂) of another. This process releases a molecule of water. When many amino acids are joined by peptide bonds, they form a long, unbranched chain called a polypeptide, which then folds into a specific three-dimensional structure to become a functional protein.
6. What are 'conditionally essential' amino acids and why are they important?
Conditionally essential amino acids are typically considered non-essential because the body can produce them under normal circumstances. However, during periods of significant illness, injury, or stress, the body's demand for these amino acids can exceed its production capacity. In these specific conditions, they become essential and must be obtained from the diet. Examples include arginine, glutamine, and cysteine, which are crucial for immune response and tissue repair.
7. Besides building proteins, what are some examples of other important functions of amino acids?
Beyond their primary role in protein synthesis, amino acids have several other critical functions in the body:
- Neurotransmitter Precursors: Tryptophan and tyrosine are used to synthesise serotonin and dopamine, respectively, which are vital for regulating mood, sleep, and focus.
- Energy Source: During fasting or prolonged exercise, the body can break down amino acids to use as an energy source.
- Metabolic Intermediates: They participate in various metabolic pathways, including the synthesis of hormones and nitrogenous bases for DNA and RNA.
- Detoxification: Certain amino acids, like arginine, are key components of the urea cycle, which helps detoxify ammonia in the body.
