Proteins are macronutrients basically made up of carbon, hydrogen, oxygen and nitrogen , although some also contain sulfur and phosphorus. These elements studied by biology (and sciences related to it) explain a good part of the functioning of our body, both in terms of its movement and, for example, in relation to our mind. However, proteins are present in all types of life forms, not just our species.
Plants synthesize proteins from inorganic nitrogen, but animals, unable to carry out this process, have to incorporate these substances through their diet. Proteins are formed by the union of several amino acids, linked by peptide bonds.
Since these biomolecules are so important to understanding what our body is like, it is useful know some of the most common types of proteins or relevant to us, and also the amino acids that form them. In this article you will find a brief explanation of these two elements, both amino acids and proteins. Let’s start with the first.
What are amino acids
As we have seen, Amino acids are the base or raw material of proteins Basically, they are the raw material from which our entire body is made: muscles, hair, bones, skin and even the brain tissue that produces our thoughts, emotions and consciousness.
Although hundreds of amino acids can be found in nature, only 20 are used in the formation of proteins. They are called: protein amino acids
The 20 types of protein amino acids
Protein amino acids, also called canonical, perform physiological functions on their own, as is the case with glycine or glutamate, which are neurotransmitters. Below you can find the 20 protein neurotransmitters:
1. Glutamic acid
This amino acid is considered the fuel of the brain and one of its main functions is to absorb excess ammonia in the body.
2. Alanine
The main task of this amino acid is that intervenes in glucose metabolism to.
3. Arginine
It is present in the body’s detoxification process , in the urea cycle and in the synthesis of creatinine. In addition, it intervenes in the production and release of growth hormone.
4. Asparagine
It is synthesized from aspartic acid, and eliminates, along with glutamine, excess ammonia from the body and intervenes in improving fatigue resistance.
5. Cysteine
Intervenes in the process of eliminating heavy metals from the body and is essential in hair growth and health.
6. Phenylalanine
Thanks to this amino acid It is possible to regulate endorphins that are responsible for the feeling of well-being Reduces excess appetite and helps relieve pain.
7. Wisteria
Helps the body in the creation of muscle mass with correct healing, prevents infectious diseases and participates in correct brain functioning.
8. Glutamine
Glutamine is found abundantly in muscles. This amino acid increases brain function and mental activity and helps solve impotence problems. In addition, it is essential to combat alcohol problems.
9. Histidine
This amino acid is the precursor of histamine It is found abundantly in hemoglobin and is necessary for the production of both red blood cells and white blood cells in the blood. In addition, it is involved in the growth process, tissue repair and the formation of myelin sheaths.
10. Isoleucine
This amino acid It is part of the genetic code and is necessary for our muscle tissue and the formation of hemoglobin. Additionally, it helps regulate blood sugar.
11. Leucine
Like the previous amino acid, intervenes in the formation and repair of muscle tissue and collaborates in the healing of skin and bones. Besides. It acts as energy in high-effort workouts and helps increase growth hormone production.
12. Lysine
Along with methionine, synthesizes the amino acid carnitine and it is important in the treatment of herpes.
13. Methionine
It is important to prevent some types of edema high cholesterol and hair loss.
14. Proline
It is responsible for the synthesis of several brain neurotransmitters related to temporary depression and also collaborates in the synthesis of collagen.
15. Serine
It is an amino acid that participates in fat metabolism and it is a precursor of phospholipids that nourish the nervous system.
16. Taurine
Taurine strengthens the heart muscle and prevents cardiac arrhythmias. Improves vision and prevents macular degeneration.
17. Tyrosine
Tyrosine stands out for its function as a neurotransmitter and can help relieve anxiety or depression.
18. Threonine
Necessary in the detoxification process and participates in the synthesis of collagen and elastin.
19. Tryptophan
Tryptophan is an essential amino acid, meaning the body itself cannot synthesize it and must be obtained through diet. It is a precursor of the neurotransmitter serotonin, associated with the mood state. Tryptophan is considered a natural antidepressant and also promotes sleep. It is also a very healthy component and easy to find in healthy diets
20. Valine
Like some of the amino acids above, It is important for the growth and repair of muscle tissues In addition, it also intervenes in the regulation of appetite.
Essential and non-essential amino acids
Amino acids can be classified as essential and non-essential. The difference between these is that the former cannot be produced by the body and, therefore, must be ingested through food. The 9 essential amino acids are :
Not all high protein foods have the same amount of amino acids. The protein with the highest amino acid content is that of eggs.
Protein classification
Proteins can be classified in different ways Below you can find the different types of protein.
1. According to its origin
One of the best-known classifications is according to origin: animal proteins and vegetable proteins
1.1. animal proteins
Animal proteins are, as their name indicates, those that come from animals. For example, proteins from eggs or pork.
1.2. Vegetable proteins
Vegetable proteins are those that come from vegetables (legumes, wheat flour, nuts, etc.). For example, soy or peanut proteins.
2. According to its function
According to its function in our body proteins can be classified into:
2.1. Hormonal
These proteins are secreted by the endocrine glands. Generally transported through the blood, hormones act as chemical messengers that transmit information from one cell to another.
You can learn more about this type of peptide hormones in our article: “Types of hormones and their functions in the human body.”
2.2. Enzymatic or catalysts
These proteins accelerate metabolic processes in cells, including liver function, digestion or converting glycogen to glucose, etc.
23. Structural
Structural proteins, also known as fibrous proteins, are necessary components for our body. They include collagen, keratin and elastin. Collagen is found in connective, bone and cartilage tissue just like elastin. Keratin is a structural part of hair, nails, teeth and skin.
2.4. Defensive
These proteins have an immune or antibody function, keeping bacteria at bay. Antibodies are formed in white blood cells and attack bacteria, viruses and other dangerous microorganisms.
2.5. Storage
Storage proteins store mineral ions such as potassium or iron. Its function is important, since, for example, the storage of iron is vital to avoid the negative effects of this substance.
2.6. Transport
One of the functions of proteins is transport within our body, because they transport minerals to the cells. Hemoglobin, for example, carries oxygen from the tissues to the lungs.
2.7. Receivers
These receptors are usually found outside the cells to control the substances that enter them. For example, GABAergic neurons contain different protein receptors in their membranes.
2.8. Contractile
They are also known as motor proteins. These proteins regulate the strength and speed of the heart or muscle contractions. For example, myosin.
3. According to its conformation
Conformation is the three-dimensional orientation that the characteristic groups of the protein molecule acquire in space, by virtue of the freedom they have to rotate.
3.1. fibrous proteins
They are made up of polypeptide chains aligned in parallel. Collagen and keratin are examples. They have high cut resistance and are insoluble in water and saline solutions. They are structural proteins.
3.2. globular proteins
Polypeptide chains that coil around themselves, causing a spherical macrostructure. They are usually soluble in water and, in general, are the transport proteins
4. According to its composition
Depending on their composition, proteins can be:
4.1. Holoproteins or simple proteins
They are made up mainly of amino acids.
4.2. Heteroproteins or conjugated proteins
They are usually composed of a non-amino acid component, and can be:
- Glycoproteins : structure with sugars
- Lipoproteins : lipid structure
- Nucleoproteins : attached to a nucleic acid. For example, chromosomes and ribosomes.
- Metalloproteins : contain one or more metal ions in their molecule. For example: some enzymes.
- Hemoproteins either chromoproteins : They have a heme group in their structure. For example: hemoglobin.