The block that builds us.

Have you ever been to a construction site, what did you see?

Books, mops, mower?
No!
Blocks, cement, sand, stones, iron rods and the likes?
Yes! When these ingredients are mixed together in their rightful proportion, a great building is formed.

This is exactly what protein does in our body. It builds us up and not that alone, its absence in the diet of a man or an animal results in malnutrition. Protein can yield energy but carbohydrates and fats will never be able to stand in place of protein.

source: CCO pixabay some sources of protein.

Protein is essential for the normal working or functioning of all body cells.
Proteins can comprise of one or many long chains of amino acid. Protein, apart from bodybuilding as its major work of giving structures to organisms, it acts as a catalyst for metabolism, and it responds to stimuli.

Proteins help in DNA replication, moving of molecules from one point to another within the body. Protein should contain at least one long peptides. Protein can't be understood without a good knowledge of amino acid.

What is Amino Acid?

Amino acids comprise mainly of Carbon, Nitrogen, Hydrogen, and oxygen, sometimes sulfur is present. Close to 500 types of Amino acids exist naturally but only about 20 are present in the genetic code. These amino acids are arranged in different ways to create different proteins, each having its specific purpose in the body with structures different from each other according to how it's constituting amino acids combine. Three different amino acids come together to form a codon. Amino acids synthesize proteins.

List of Amino acids

Chemical structures of 21 amino acids.
source:Wikipedia CCA By-SA 3.0 Author: Dancojocari

• Essential Amino acids are those ones which cannot be produced by the body but can be supplied through food. Example histidine, phenylalanine, threonine, valine, tryptophan, lysine, leucine, isoleucine, and methionine.

• Conditionally Essential Amino acids: their production can be limited during some physiological conditions as in case of premature childbirth or at certain ages. Examples are tyrosine, cysteine, glycine, arginine, proline, and glutamine.

• Non- essential Amino acids are those which can be produced by the body. Example aspartic acid, alanine, glutamic acid, serine, and asparagine.

Types of protein

Protein occurs in various forms, which are but not limited to the following :

Based on the sequence of their nucleotide in the gene:

A straight chain of amino acid will make a Polypeptide.

Polypeptides with 20 to 30 residues are called oligopeptide or simply peptides (they are not considered as protein most times).
Since the gene which is the smallest unit of life controls so much, it controls the arrangement of amino acid in the protein.

Based on the type of protein foods:

Complete proteins: it contains all the essential amino acids. Which are found mostly in animal products (meat, milk, and eggs).

Complementary proteins: This occurs when two or more incomplete protein food source are combined to get a complete protein. Example of pea and rice.

Incomplete proteins: Foods belonging to these group contains one essential amino acid at least but there is an imbalance of other amino acids in relation with the one present. These foods are mainly of plant origin such as beans.

Based on the characteristics of the side chains:

Amino acids contain amine, carboxyl groups, a side chain which stands specifically for each amino acid. The classification are;

Aliphatic: alanine, glycine, isoleucine, leucine proline, valine.

Amidic (containing amide group): glutamine, asparagine.

Aromatic: phenylalanine, tyrosine, tryptophan.

Basic: lysine, histidine, arginine.

Acidic: aspartic acid, glutamic acid.

Hydroxylic: threonine, serine.

Sulfur-containing: cysteine, methionine.

Based on the properties of their main products during catabolism

• Ketogenic: It has products that do not have the ability to form glucose, which could be used for lipid synthesis.

• Glucogenic: Its products can form glucose through a process called gluconeogenesis.

• Amino acids can be destroyed to produce products having the ability to form glucose and products which cannot.

Based on the attraction of the side chain when in contact with polar solvent

Charged: These amino acids become charged when in contact with a polar solvent. They often form salt bridges. Examples are Arginine, Lysine, Aspartic acid, Glutamic acid

Polar: These amino acids act as proton donors or acceptors especially, during hydrogen bonding. Examples are Glutamine, Asparagine, Histidine, Serine, Threonine, Tyrosine, Cysteine, and Tryptophan

Hydrophobic: These amino acids are usually buried inside the protein and in aqueous solution, they do not take part in hydrogen bonding. Example are Alanine, Isoleucine, Leucine, Methionine, Phenylalanine, Valine, Proline, Glycine.

Hydrophilic: They do not have a side chain making it difficult to be classified in the above groups but they interact in the aqueous solution due to polarity. Examples are Glycine and it's found on the surface of protein within the coil region

Non-polar: They equally do not have side chains but the difference is that they provide rigidity to the polypeptide chain. An example is a proline which is also found in loop regions of the protein.

Functions of some Amino acids

Tyrosine helps to manage depression, stress and the effects of stress syndrome. It helps in treating skin problems like vitiligo, it detoxifies the body of drugs and caffeine addiction.

Alanine aid the immune system when it produces antibodies provide energy for the muscle and it's the primary amino acids for acid metabolism.

Cysteine is capable of promoting the production of iron in iron deficiency. It is responsible for the inactivation of insulin in the bloodstream. It helps in increasing red blood cells production

Asparagine serves as a neurotransmitter. It is highly concentrated in the brain (hypothalamus), this helps in short-term memory, maintains the equilibrium of the nervous system and it is needed for changes in amino acids from one to another.

Arginine helps in healing wounds, chest pain, heart disease, for bodybuilding, prevents tissue wear and tear, for treating burns.

Aspartic acid is an excitatory neurotransmitter, agent of transamination, detoxifier of ammonia, and used in DNA coding. It protects the liver.

Glutamine fuels body cells give nitrogen to the cell, provides Small intestine with the right energy requirements, synthesizes protein, and maintains the pH of the liver.

Histidine stimulates the inflammatory response of the skin. It is needed for growth and tissue repair. Having a high concentration of hemoglobin, it is useful in anemia treatment. Histidine is essential in the production of Red blood cell and white blood cells.

Glycine keeps the sugar level regulated by providing the glucose needed. It helps in muscle breakdown by increasing the amount of creatine which helps to build the muscle. Glycine prevents skin damage via ultraviolet rays and keeps it firm.

Food Sources of protein

Oat, cheese, milk, beef, pea, beans, eggs, cashew, almonds, chicken, fish, soya bean, pigeon peas, kidney beans, shrimp, lobster, groundnut.

                         Reference

https://ghr.nlm.nih.gov/primer/howgeneswork/protein

https://www.britannica.com/science/protein
http://www.cryst.bbk.ac.uk/education/AminoAcid/the_twenty.html

http://www.cryst.bbk.ac.uk/education/AminoAcid/the_twenty.html

https://en.m.wikipedia.org/wiki/Essential_amino_acid#Essentiality_vs._conditional_essentiality_in_humans

https://en.m.wikipedia.org/wiki/Amino_acid