What are Amino acids?

Amino acids: Organic compounds that have both amino (-NH 2 ) and carboxylic (-COOH) groups in their molecules are called amino acids.

Water decomposition of proteins yields a mixture of α amino acids, so α amino acid is the basic structural unit of the protein.

All the protein we eat, whether it is meat or plant origin, is composed of amino acids. Amino acids are the basic building blocks of proteins, and there are 20 different amino acids.

The combination of amino acids in the food we eat may be different, so it will affect how the body uses amino acids, and each amino acid has a very unique role in the body.

This 20 amino acids can be divided into two types: essential amino acids ( EAA ) and nonessential amino acids (NEAAs).

How many amino acids are there?

The 20 to 22 amino acids that comprise proteins include: 

  • Alanine
  • Arginine
  • Asparagine
  • Aspartic Acid
  • Cysteine 
  • Glutamic acid
  • Glutamine 
  • Glycine
  • Histidine
  • Isoleucine
  • Leucine
  • Lysine
  • Methionine
  • Phenylalanine
  • Proline
  • Serine 
  • Threonine
  • Tryptophan 
  • Tyrosine 
  • Valine
  • Selenocysteine
  • Pyrrolysine (not used in human protein synthesis)

Of these 20 amino acids, nine amino acids are essential: 

  • Phenylalanine
  • Valine
  • Tryptophan
  • Threonine
  • Isoleucine
  • Methionine
  • Histidine
  • Leucine
  • Lysine

Structure of amino acids

What are Amino acids?, Types, Method, Essential & Non-Essential, Structure of amino acids

Types of amino acids

1. Based on the number of -NH 2 and -COOH group: –

(a) Neutral amino acid: It contains the same number of -NH 2 and -COOH groups.

(b) Alkaline amino acids: They contain more number of -NH 2 groups than -COOH group, hence they are called alkaline amino acids.

(c) acidic amino acids: These -NH 2 numbers then -COOH groups of the group is much more so it is called acidic amino acids.

2. Depending on the position of the -NH 2 group relative to the COOH group :

(a) α amino acids: In these COOH and -NH 2 groups are attached to the same C.

(b) β amino acids

(c) γ amino acid

Structure and Stereoscopic Incompatibility: All α amino acids except glycine indicate optical isomerism because they contain kirtle / asymmetric C.

Amino acids are named D / L relative to the NH 2 group.

Method of preparation:

1. Streaker Synthesis: In this method aldehyde or ketone is reacted with a mixture of NH 4 Cl and NaCN then cyano hydrin is formed which gives α amino acids by amination and water decomposition.

2. Gabriel thalimide synthesis: The reaction of potassium thalimide with α hello acid results in water decomposition of the product to give α amino acid, this is called gebryl thalimide synthesis.

3. By Arlenmeyer reaction: Azlactone is formed by heating benzaldehyde and hepatic acid in the presence of acetic and hydride and sodium acetate, which is heated by heating in a 1% NaOH solution and decomposed by sodium amalgam to produce α amino acids. .

4. Follicle synthesis: In this method, α keto acid reacts with NH 3 to form aldemino carboxylic acid, which reduces α amino acids.

5. By malonic esters: From the malonic esters, α halogen acids are formed, whose amino acids are formed by the amination.

6. By Curtius reaction: In this reaction, malonic ester is converted into α amino acid.

7. Synthesis of Dashops: Alkyl cyano acetic ester is formed by reduction of the product obtained by condensation of aldehyde and cyano acetic ester which further reacts to form α amino acids.

8. Hafmann degradation: In this reaction the α-amido ester forms α amino ester by Hofmann degradation reaction, whose water decomposition produces α amino acids.

Amino acids: Amino acids are monocarboxylic or dye carboxylic acids having one or two amino groups. Their common formula is R-CH-NH 2 COOH. They are also made of carbon, hydrogen, oxygen, nitrogen (C, H, O, N) and sometimes sulfur. Amino acids have an amino group and an acidic group on the same carbon. Example: α-carbon.

Amino acid amphoteric molecules or jitter ions are dipolar ions because they have an acidic (carboxylic) and an alkali (a group of amines) so it has both positive and negative charges.

The R-group represents hydrocarbons which may be a small unsaturated group or chain or a branched-chain or a cyclic group. There are several types of amino acids, depending on the nature of the R-group. There are 20 types of amino acids found in proteins, these are mainly of four types –

1. Unipolar R-group: R-group is inelastic and anti-water – example: Alanine, valine

2. Polar uncharged R-group: R-group polar water is lubricated and unharmed – example: serine

3. Uncharged polar R-group: Lysine, arginine

4. Negative polar R – group: Glutamic acid, Aspartic acid

Glycine is the simplest and smallest amino acid. The (-NH) amino group is found in the proline and hydroxyproline (-NH 2 ) amino groups. Therefore, they are also called amino acids. Glutamic acid and serine are polar amino acids while alanine is non-polar amino acids. Amino acids can be natural (eg: glycine, alanine, valine, and leucine), acidic (eg: aspartic acid and glutamic acid), alkaline (eg: arginine and Lysine). Cystine, cysteine ​​and methionine are sulfurized amino acids. Serine and threonine are alcoholic amino acids. Phenylalanine, tyrosine, tryptophan, etc. are aromatic amino acids while histidine, proline, and hydroxyproline are heterozygous amino acids.

All amino acids are laevorotatory. The only glycine displays dextrorotatory. Protein amino acids are mainly of three types. Arnithine, citrulline (both are involved in the ornithine cycle for the synthesis of urea.) And diminopimelic acid. The ionized nature of the -NH 2 and -COOH groups of amino acids is an individual trait, so the composition of amino acids in solutions with different pH changes.

There are two types of amino acids –

1. Essential Amino Acids

2. Non Essential amino acids

Essential amino acids cannot be synthesized in the human body whereas unnecessary amino acids can be.

Seven essential acids are found in the body of animals while 8 essential amino acids are found in the human body.

These leucine isoleucine valine, phenylalanine, tryptophen, lysine, methionine. In humans, threonine is an extra amino acid. The two amino acids arginine and histidine are semi-essential because they are synthesized at a slower rate in the human body.

Proteinless Amino Acids

Protein amino acids are not found in proteins but are found in protein substances in a free or conjugate state, the number of which is more than 180.

(i) Arnithine and citrulline participate in the urea cycle.

(ii) D-alanine and D-glutamine acid are the constituents of peptidoglycan in the bacterial wall.

(iii) Gamma is aminobutyric acid or GABA which inhibits the opening of the chloride channel.

(iv) Many molecules correspond to amino acids in antibiotics that inhibit protein synthesis, eg: D-phenylalanine in Gramicidin-S.

(v) Actinomycin-D is an inhibitor of RNA formation in which D-valine is present.

Peptide bond

The peptide or amide bond is the linkage that is established during the condensation reaction between the amino group of one amino acid and the carboxylic group of another amino acid. A water molecule is free in it. The peptide bond has a -NH-CO-linkage. The condensation reaction between two amino acids forms a dipeptide that has a free carboxylic group at one end and a free amino group near the other end. For this reason, a dipeptide behaves like single amino acid and can condense with other amino acids to form a chain of amino acids. If the number of amino acids is 10 or less, then they are called oligopeptides or simply peptides. The polypeptide contains a large number of amino acids.

Functions of amino acids

1. These proteins act like building blocks and aid in their synthesis through polymerization.

2. Tyrosine is converted into thyroxine and adrenaline hormones, it is also converted into skin pigment, which is called millennia. Glycine forms the heme and protein of hemoglobin in the blood. Tryptophan is used to produce vitamin nicotinamide and a plant hormone indoleacetic acid (IAA or Auxin).

3. Mono amino acids are converted to glucose after deamination with the loss of one amino group.

4. A protein amino acids act as constituents of various types of organisms.

5. Certain amino acids in the liver such as citrulline and ornithine participate in the urea cycle.

6. Derivatives of certain amino acids in the form of amide help in the accumulation of nitrogen.

7. This histidine is formed by the decarboxylation of amino acids. It can occur in all cell types. Histamine is formed during an allergic reaction. This causes capillaries to dilate, blood pressure increases and smooth muscles (bronchi, uterus) become compressed and gastric secretions are increased.

8. Amination of excess amino acids results in deamination and their organic acids are converted into glucose and other carbohydrates.

9. It is a co-enzyme of oxidation-reduction reactions, in which the tripeptide of glutamic acid, cysteine ​​, and glycine. This chemical is important to prevent oxidative damage of erythrocytes.

10. Many hormones are peptides by nature, oxytocin (birth hormone, milk ejection hormone) and vasopressin (ADH antidiuretic hormone, urine concentrating hormone) are posterior pituitary peptides.

11. Aspartame is not unbearable after the taste of certain, it does not suit a person suffering from phenylketonuria.

Amino acids

Amino acids are the formation of proteins. There are a total of 20 amino acids in our nature, out of which only ten amino acids are necessary.

1. Essential amino acids: histidine, lysine, phenylalanine, methionine, lysine, isoleucine, valine, tryptophan, arginine, and threonine.

2. Non Essential amino acids: glutamine, carnitine, cysteine, alanine, asparagine, aspartic acid, glycine, proline, serine, tyrosine.


Water is a common chemical substance whose chemical formula is v2. This is the basis of the life of all beings. All the major components of the cell dissolve in water. Water is also called all-solvent. Substances that dissolve well in water such as salts, sugars, acids, alkalis, and some gases, especially oxygen and carbon dioxide, are called hydrophilic. And those that do not dissolve are called hydrophobic.


They play a very important role in maintaining the physical condition of cells and tissues. Examples of these are calcium, sodium, potassium, iron, etc.

What are the Effects of amino acids on the human body?

✓ Make protein

Amino acids are the basic elements that makeup proteins.

When certain human cells need protein (for example, when the human body “grows” muscle), the arrangement of amino acids connects to form RNA (i.e., a copy of ribonucleic acid, DNA).

To complete this process, all specific amino acids must be available, otherwise, the required protein cannot be synthesized. After the amino acid sequence is formed, it folds and curls to form a secondary structure.

A large number of alpha helices and beta sheets (protein secondary structure) are connected to form a tertiary structure. Each protein has a specific shape and performs the different functions it needs.

Since each protein is different, various proteins perform specific and different biological functions. When your muscles are minimally invasive, special proteins are needed to rebuild the muscles. This is why amino acid supplements (such as BCAA branched-chain amino acid powder ) are very popular among fitness enthusiasts.

 ✓Promote cardiovascular health

Nitric oxide can help lower blood pressure because it helps relax the tiny muscles in the blood vessels, relax the blood vessels, thereby reducing stress, which is essential for cardiovascular health. The amino acid is a necessary factor for the synthesis of nitric oxide.

Lower blood pressure helps prevent atherosclerosis because plaque is less likely to form in the arteries, which prevents cardiovascular diseases such as heart attacks or strokes. Also, nitric oxide is the main active component of nitroglycerin. Drugs containing nitroglycerin are carried by many patients with coronary heart disease. It can relieve symptoms such as chest pain caused by coronary heart disease.

 ✓Generate neurotransmitters

There are several well-known amino acids, such as tyrosine and tryptophan, that can produce neurotransmitters. Neurotransmitters help complete the neural response, which can improve the body’s response speed, concentration, and alertness.

Also, tryptophan produces a hormone called “serotonin” to improve mood. Tyrosine also helps synthesize epinephrine (epinephrine can quickly provide energy supply and response speed). When the two amino acids tyrosine and tryptophan work together, they can increase the body’s energy level and promote brainpower.

Eating high-protein foods or taking amino acid supplements will increase the level of these amino acids, allowing users, especially bodybuilders, to benefit from them.

  ✓ Helps improve metabolism

Another important effect of amino acids on the human body is to help maintain metabolism and energy levels.

Although the preferred sources of energy are complex carbohydrates and fats, amino acids can also be used as energy sources when needed by the human body. For example, bodybuilders usually reduce their carbohydrate intake to a minimum to control body fat before competitions-which may lead to a decline in body energy levels. Taking some amino acid supplements such as BCAA branched-chain amino acid powder can additionally help increase energy levels and effectively prevent muscle breakdown.

 ✓ Antioxidant properties

Glutathione is an important antioxidant in the human body. It is formed by the combination of glutamic acid, cysteine ​​, and glycine.

Glutathione is a key component to maintain the normal functioning of the human immune system, helps fight infection, eliminates disease-causing microorganisms and infected cells, and allows cells to perform normal functions.

 ✓ Source of amino acids

Amino acids are divided into two types, essential and non-essential. Simply put, essential amino acids are amino acids that the human body cannot synthesize by itself, and must be supplemented through diet and other food sources (such as health supplements, etc.).

  • Non-essential amino acids can be self-made or synthesized in the body, but the best results are usually achieved through dietary intake, especially for bodybuilders with high nutritional needs.
  • Most amino acids are found in animal foods, so vegetarians and vegans often find it difficult to obtain the essential amino acids they need. For this reason, taking amino acid supplements is very necessary.

What is The role of amino acids?

The efficacy and role of amino acids. Amino acids are the basic structural units that makeup proteins. They can provide energy for the body and the brain and are the source of all living substances. So, what are the effects and functions of amino acids?

The role of amino acids

  1. The digestion and absorption of protein in the body are accomplished through amino acids: as the first nutrient element in the body, protein has an obvious role in food nutrition, but it cannot be used directly in the body. It is used by turning into small amino acid molecules.
  2.  Play the role of nitrogen balance: when the quality and amount of protein in the daily diet are appropriate, the amount of nitrogen ingested is equal to the amount of nitrogen excreted from the feces, urine, and skin, which is called the total balance of nitrogen. It is the balance between continuous synthesis and decomposition of protein and amino acids. The daily protein intake of normal people should be kept within a certain range. When the intake of food is suddenly increased or decreased, the body can still regulate the metabolism of protein to maintain nitrogen balance. Ingestion of excessive protein, beyond the body’s ability to regulate, the balance mechanism will be destroyed. If you don’t eat protein at all, the tissue protein in your body will still be decomposed, and negative nitrogen balance will continue to occur. If you don’t take corrective measures in time, it will eventually lead to the death of antibodies.
  3. Converted into sugar or fat: the a-keto acid produced by the catabolism of amino acids is metabolized along the metabolic pathway of sugar or fat with different characteristics. a-keto acid can be re-synthesized into new amino acids, or converted into sugar or fat, or enter the tri-carboxyl cycle to oxidize and decompose into CO2 and H2O, and release energy.
  4. Participate in the formation of enzymes, hormones, and some vitamins: the chemical nature of enzymes is a protein (amino acid molecular composition), such as amylase, pepsin, cholinesterase, carbonic anhydrase, transaminase, etc. The components of nitrogen-containing hormones are proteins or their derivatives, such as growth hormone, thyroid-stimulating hormone, adrenaline, insulin, enterotoxin, and so on. Some vitamins are converted from amino acids or combined with proteins. Enzymes, hormones, and vitamins play a very important role in regulating physiological functions and catalyzing metabolism.
  5. The requirement of human essential amino acid: The requirement of adult essential amino acid is about 20% to 37% of the requirement of protein.

What are essential amino acids?

All proteins are composed of amino acids, and there are 9 essential amino acids in total. If your diet contains 9 essential amino acids, then your body can manufacture the remaining 11 non-essential amino acids on its own.

This is the main difference between essential amino acids and non-essential amino acids. The human body cannot produce essential amino acids, but it can produce non-essential amino acids, but this does not mean that non-essential amino acids are not important for muscle formation.

When a food contains all 9 essential amino acids, it is called a complete protein.

9 essential amino acids

  • Histidine-used for the development and maintenance of healthy tissues.
  • Isoleucine-Used for blood clotting and muscle repair.
  • Leucine-a branched-chain amino acid involved in muscle growth.
  • Lysine-participates in the production of collagen and is essential for bone health.
  • Methionine-a powerful antioxidant.
  • Phenylalanine-helps produce hormones.
  • Threonine-used in the formation of bones and cartilage.
  • Tryptophan – participates in promoting sleep and produces serotonin.
  • Valine-helps prevent muscle breakdown and remove excess protein from the liver.

Most of the amino acids we eat are directly related to our muscles. One of the main functions of essential amino acids is to provide nutrition to the lean muscles in our body. This can be manifested in two ways: Essential amino acids provide the basis for new muscle growth when calories are left, and help prevent muscle loss when calories are insufficient.

The efficacy of amino acids

Some benefits of eating and supplementing essential amino acids:

  1. Increase the production of mitochondria in the myocardium and skeletal muscle (mitochondria are mainly responsible for breaking down fatty acids and converting them into energy). This is very important for people who often do endurance exercise because they will be able to break down more fatty acids for fuel by supplementing essential amino acids, thereby improving performance and delaying fatigue.
  2. Prevent oxidative damage related to inflammation. When we train and exercise, it is normal for our body to suffer a certain degree of damage. What we want to prevent is excessive inflammation, and essential amino acids help to minimize it.
  3. Provide signals of new muscle growth and help its growth. Essential amino acids can tell your body that it is time to start building new muscles to cope with the stress on the body and lay the foundation for muscle growth.
  4. Improve physical fitness. Essential amino acids can reduce fatigue under tension and make the bodywork longer. Essential amino acids can help improve strength, muscle growth, and endurance.
  5. Lose weight. Essential amino acids contribute to the activity of fatty acids. And essential amino acids contain little or no calories per gram, so they can be used to create a calorie gap for the body while maintaining lean muscle mass.
  6. Improve immune function. Essential amino acids can act as powerful antioxidants and help keep the immune system strong.
  7. Help prevent muscle protein breakdown. There are two components to developing muscle tissue-the first is muscle growth, and the second is to prevent muscle breakdown. Studies have shown that essential amino acids help resist muscle protein breakdown.
  8. The above are some introductions about amino acids and essential amino acids. I hope that everyone can have a more basic and comprehensive understanding of amino acids.
  9. Longevity.If the elderly lack protein in their bodies, they will decompose more and their synthesis will slow down. Therefore, generally speaking, the elderly need more protein than young adults, and their requirements for methionine and lysine are also higher than those of young adults. Elderly people over 60 should consume about 70 grams of protein a day and require a complete range of essential amino acids contained in protein and appropriate proportions so that high-quality protein can prolong life.
  10. Amino acids. are mainly used in medicine to prepare compound amino acid infusions, as well as therapeutic drugs and synthetic peptide drugs. At present, there are more than 100 kinds of amino acids used as medicines, including 20 kinds of amino acids that constitute proteins and more than 100 kinds of amino acids that constitute non-proteins.
  11. Compound preparations composed of a variety of amino acids occupy a very important position in modern intravenous nutritional infusion and “element diet” therapy. They play a positive role in maintaining the nutrition of critically ill patients and rescuing the lives of patients and become one of indispensable medicines in modern medicine. One.
  12. Glutamic acid, arginine, aspartic acid, cystine, L-dopa, and other amino acids act alone to treat some diseases, mainly for the treatment of liver diseases, digestive tract diseases, encephalopathy, cardiovascular diseases, respiratory diseases, and For improving muscle vitality, pediatric nutrition, and detoxification, etc. Also, amino acid derivatives have shown promise in cancer treatment.

What are Amino acids?, Types, Method, Essential & Non-Essential, Structure of amino acids


Categories: Biochemistry