Functions of amino acids

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LEARNING OBJECTIVES

In this article, author has explained the functions of essential and non-essential amino acids.

Essential amino acids

The essential amino acids perform the following functions:

  • Histidine is a precursor of various hormones which are essential for the function of the kidney, neurotransmission, and gastric secretion. Histidine also plays role in the immune system.  It produces red blood cells and hemoglobin. Histidine also produces anti-inflammatory responses. Histidine also catalyzes several enzymes. The deficiency of histidine leads to kidney diseases, anemia, oxidative stress, and anti-inflammatory disorders.
  • Isoleucine is one of the branched amino acids. Isoleucine enhances protein synthesis. It is involved in the formation of muscle tissues. It also increases the consumption of glucose and the development of the intestine. Isoleucine is also necessary for the proper functioning of the immune system.
  • Lysine is an important component of growth factors. It plays role in cell division and growth. When lysine solutes are used to increase the process of healing, it leads to less scar tissue formation. Lysine also helps in the metabolism of lipids. It helps in the fixation of calcium in bones. Lysine deficiency can cause anemia, impaired fatty acid metabolism, slow healing of the wound, lower muscle mass, and defects in connective tissues. A high level of lysine can cause neurological disorders.
  • The amino acid methionine has sulfur which is necessary for cartilage and liver health. It also modifies hair structure and increases the strength of nails. Methionine is also used to treat kidney stones. It controls the attack of pathogenic bacteria.
  • Phenylalanine helps in maintaining the functions of the nervous system. It assists to enhance memory power. It also plays role in fat oxidation.
  • Threonine functions to balance the neurotransmitter in the brain. It helps in muscle tissue production and immune system functions.
  • Tryptophan is a precursor for niacin (vitamin B3), melatonin, and serotonin. Thus, it maintains sleep and mood. The tryptophan codon is essential for the formation of polypeptides and proteins.

Non-essential amino acids

Non-essential amino acids perform the following functions:

  • Alanine and glutamine are synthesized in the skeletal muscles. Both increase the energy supply. They are needed for the healthy functioning of the nervous system. Alanine also protects the cardiovascular system and removes toxins from the body.
  • Arginine increases T-cell production and thus play role in the immune system. It also enhances the synthesis of hormones and proteins, detoxifies the kidneys, and increases the process of wound healing.
  • Asparagine plays role in glycoprotein synthesis. It transports nitrogen to body cells for the formation of nitrogenous bases which in turn are required for DNA synthesis.  It improves the stamina of the body.
  • Aspartic acid plays role in metabolism. It is part of the urea cycle and citric acid cycle and thus acts as a precursor for the other amino acids.
  • The sulfur-containing cysteine works as an antioxidant and provides resistance to the body. It is needed for collagen production. Cysteine also affects the texture and elasticity of the skin. It is also necessary for the production of proteins, coenzyme A, glutathione, and hydrogen sulfide. Cysteine is also a precursor for pyruvate and taurine.
  • Glutamic acid acts as an excitatory neurotransmitter in the central nervous system. It is also a precursor of GABA (gamma-aminobutyric acid). Glutamic acid also helps in lowering blood pressure. It is necessary for the production of RNA and DNA.
  • During stress conditions, the proline provides energy to the body. It is also involved in the formation of collagen. Proline repairs the damage issues and regenerates new skin. It prevents the thickening and hardening of the walls of arteries.
  • Serine transfers methyl groups therefore it is necessary for the production of creatine, epinephrine, DNA, and RNA. It also forms glycine, cysteine, taurine, and phospholipids.  It produces immune system proteins.
  • Tyrosine is a precursor of catecholamines, dopamine, noradrenaline, thyroxin, and melanin. Tyrosine is also necessary for polypeptide and protein production. It is also necessary for the production of thyroid hormones, T3 and T4.