Amino Acids – The Building Blocks

Amino Acids

Amino acids are small particles that are the building blocks of proteins. Proteins serve as structural support inside the cell and they perform numerous important chemical reactions. Each protein is a molecule comprised of different combinations of 20 types of smaller, simpler amino acids. Protein molecules are long chains of amino acids that are folded into a three-dimensional shape.

Chemically, an amino acid is a particle that has a carboxylic acid group and an amine group that is each connected to a carbon atom called the α carbon.

Structure of Amino Acid

Amino acids are the monomers that comprise proteins. Each amino acid has the same basic structure, which consists of a central carbon atom, likewise called the alpha (α) carbon, bonded to an amino group (NH2), a carboxyl group (COOH), and to a hydrogen atom. In the aqueous environment of the cell, both the amino group and the carboxyl group are ionized under physiological conditions, and so have the structures -NH3+ and -COO–, respectively.

Every amino acid likewise has another atom or group of atoms bonded to the central atom referred to as the R group. This R group, or side chain, provides each amino acid protein’s specific characteristics, including size, polarity, and ph. Amino acids have a central asymmetric carbon to which an amino group, a carboxyl group, a hydrogen atom, and a side chain (R group) are connected.

This amino acid is unionized, but if it were positioned in the water at pH 7, its amino group would pick up another hydrogen and a positive charge, and the hydroxyl in its carboxyl group would lose and hydrogen and acquire a negative charge.


Characteristics of Amino Acids

The chemical structure of the side chain figures out the characteristics of the amino acid. Amino acids such as valine, methionine, and alanine are nonpolar (hydrophobic), while amino acids such as serine, threonine, and cysteine are polar (hydrophilic).

Further Reading:  Reactions of Lipids - Saponification, Hydrogenation, Peroxidation, Rancidity

The side chains of lysine and arginine are positively charged so these amino acids are likewise known as basic (high pH) amino acids. Proline is an exception to the basic structure of an amino acid due to the fact that its R group is linked to the amino group, forming a ring-like structure.

Amino acids are represented by a single upper-case letter or a three-letter abbreviation. For instance, valine is known by the letter V or the three-letter symbol val.

Classification of Amino Acids

The 20 amino acids are classified into two different amino acid groups. Essential amino acids and Non-essential amino acids together comprise the 20 amino acids. Out of the 20 amino acids, 9 are essential amino acids, and the others are Non-essential amino acids. Let’s see each different amino acid according to their category.

Essential Amino Acids

The nine necessary amino acids perform a number of important and varied tasks in your body:


Phenylalanine is a precursor for the neurotransmitter’s tyrosine, dopamine, epinephrine, and norepinephrine. It plays an essential role in the structure and function of proteins and enzymes and the production of other amino acids.


Valine is among three branched-chain amino acids, suggesting it has a chain branching off to one side of its molecular structure. Valine helps promote muscle development and regeneration and is associated with energy production.


Threonine is a principal part of structural proteins such as collagen and elastin, which are important elements of the skin and connective tissue. It also plays a role in the fat metabolic process and immune function.


Though often associated with causing sleepiness, tryptophan has numerous other functions. It’s required to keep appropriate nitrogen balance and is a precursor to serotonin, a neurotransmitter that regulates your cravings, sleep, and state of mind.

Further Reading:  Chromatography: Paper Chromatography & Uses of Chromatography


Methionine plays a crucial function in metabolism and detoxing. It’s likewise required for tissue growth and the absorption of zinc and selenium, minerals that are essential to your health.


Like valine, leucine is a branched-chain amino acid that is crucial for protein synthesis and muscle repair. It likewise assists regulate blood sugar levels, stimulates injury healing, and produces growth hormones.


The last of the 3 branched-chain amino acids, isoleucine is involved in the muscle metabolic process and is heavily concentrated in muscle tissue. It’s likewise important for immune function, hemoglobin production, and energy regulation.


Lysine plays significant functions in protein synthesis, hormone and enzyme production, and the absorption of calcium. It’s also important for energy production, immune function, and the production of collagen and elastin.


Histidine is used to produce histamine, a neurotransmitter that is essential to immune response, digestion, sexual function, and sleep-wake cycles. It’s important for maintaining the myelin sheath, a protective barrier that surrounds your afferent neuron.

Non-Essential Amino Acids


Glutamine is among the most typical amino acids in the body. Glutamine protects the stomach and intestinal system. In particular, glutamine is used to produce energy for the digestive system. Glutamine promotes the metabolization of alcohol to protect the liver.


Aspartate is among the amino acids that are most functional for energy. Aspartate is among the amino acids placed most carefully to the tricarboxylic acid (TCA) cycle in the body that produces energy. The TCA cycle is like the engine that powers cars. Each cell in our bodies functions to produce energy.


Inside the body, glutamate is used as an important source of vital amino acids.


Arginine plays a crucial role in opening the veins to boost blood circulation. Nitric oxide that opens up the veins is made from arginine. Arginine is a useful amino acid for the removal of excess ammonia from the body. Arginine increases immunity.

Further Reading:  Carboxylic Acids: Physical Characteristics, Reactivity and Uses


Alanine supports the function of the liver. Alanine is utilized to make glucose that is required by the body. Alanine improves the metabolization of alcohol.


Proline is among the amino acids consisted of in collagen that makes up skin tissue. Proline is among the most essential amino acids to the natural moisturizing factor (NMF) that keeps skin moist.


Cysteine reduces the amount of black melanin pigmentation. Cysteine abounds in head hair and body hair. Cysteine increases the quantity of yellow melanin instead of black melanin.


An amino acid that was discovered from asparagus. Both asparagine and Aspartate are placed close to the tricarboxylic acid (TCA) cycle that produces energy.


An amino acid utilized to make phospholipids and glyceric acid.


A non-essential amino acid that is made in the body. Glycine abounds in the body. It functions as a transmitter in the main nervous system and helps regulate body functions such as mobility and sensory perception. Glycine comprises one-third of collagen.


Tyrosine is used to make lots of types of helpful amines. Tyrosine is grouped as a fragrant amino acid together with phenylalanine and tryptophan.


Amino acids are the building blocks of proteins. An amino acid contains an amino group NH2, a carboxyl group COOH, a hydrogen atom and a functional group R. they all are bonded to the central carbon atom.

The nature of the R group determines the chemical properties of each amino acid. Amino acids are linked together by peptide bonds. Two amino acids are linked together by a peptide bond to form a dipeptide e.g., alanine and glycine form glycylalananine.

Peptide bonds are covalent bonds. The carboxyl group of one amino acid bonds to the amino group of another amino acid in a peptide bond. The chain of amino acids can vary from fewer than 50 to more than 2000 amino acids in different proteins.