Metabolism of Amino Acids

• Nonessential amino acids are synthesized from intermediates of metabolism.
• Essential amino acids include Phenylalanine, Valine, Threonine, Tryptophan, Methionine, Leucine, Isoleucine, Lysine, Histidine, and Arginine.
• Nonessential amino acids include Alanine, Asparagine, Aspartic acid (Aspartate), Cysteine, Glutamic acid (Glutamate), Glutamine, Glycine, Hydroxyproline, Hydroxylysine, Proline, and Serine.
• Nitric oxide (NO) is synthesized through the action of an enzyme called nitric oxide synthase (NOS), which uses L-arginine, oxygen (O2), and NADPH as substrates to produce NO and L-citrulline.
• Immune System: NO has an essential role in the immune response, involved in macrophage function, playing a part in the immune system's defense against pathogens by enhancing the killing ability of immune cells.
• Nitric oxide (NO) is a signaling molecule with diverse roles in the body, including vasodilation, neurotransmission, platelet function, and immune system function.
• Histidine is the precursor of Histamine, Carnosine, Ergothioneine, Anserine, Homocarnosine.
• Arginine is the precursor of the Nitric oxide and is also used for urea production.
• Histamine is a crucial chemical compound that plays multiple roles in the body, acting as a mediator for various cellular responses, including allergic reactions, inflammatory reactions, gastric acid secretion, and potential role in neurotransmission.
• Vasodilation: NO acts as a vasodilator by relaxing the smooth muscle cells in blood vessels, leading to the widening of blood vessels and increased blood flow, which is essential in regulating blood pressure and overall cardiovascular function.
• Platelet Function: NO helps prevent platelet aggregation,
• Neurotransmission: In the nervous system, NO functions as a neurotransmitter
• Tryptophan is used for NAD production and is present in smaller quantities within the central nervous system, where it acts as a neurotransmitter, and in platelets.
• Tyrosine is formed from phenylalanine by phenylalanine hydroxylase, an enzyme whose deficiency is the root cause of PKU.
• Amino acids whose catabolism yields either Acetyl CoA or Acetoacetyl CoA are termed ketogenic.
• Proline is formed from glutamate by cyclization and reduction reactions.
• Important products derived from amino acids include Heme, Purines, Pyrimidines, Hormones, Neurotransmitters and Biologically active peptides.
• Once amino acids are metabolized their products directly enter the pathways of intermediary metabolism, resulting either in the synthesis of Glucose, lipids, or in the production of energy through their oxidation to CO2 and H2O by the citric acid cycle.
• Serine and Glycine arise from 3-phosphoglycerate and can also be formed from glycine through the transfer of a hydroxymethyl group.
• The catabolism of amino acids found in the proteins involves the removal of alpha amino groups, followed by the breakdown of the resulting carbon skeletons.
• Amino acids whose catabolism yields Pyruvate or one of the Intermediates of the citric acid cycle are termed glucogenic
• Alanine, Aspartate and Glutamate are synthesized by the transfer of an amino group to the alpha-keto acids Pyruvate, Oxaloacetate and alpha-keto glutarate (respectively)
• Glutamine and Asparagine are synthesized from Glutamate by amidation, a reaction catalysed by glutamine synthetase and asparginine synthetase respectively.
• Cysteine is synthesized from homocysteins, which condenses with serine, forming cystathionine, which is hydrolyzed to alpha-ketobutyrate and cysteine.
• The carbon skeletons of amino acids are converted to Pyruvate, Acetyl-CoA, Acetoacetyl-CoA, Oxaloacetate, Alpha-ketoglutarate, Fumarate, and Succinyl-CoA.
• Cyclic amino acids are automatically essential, it is really hard for our body to synthesize these.
• Amino acids synthesized from intermediates of metabolism include Alanine, Aspartate, Glutamate, Proline, Serine, and Glycine.
• Glutamate, Aspartate, and Alanine are synthesized by the transfer of an amino group to the alpha-keto acids.
• Tryptophan is the precursor of Serotonin, Nicotinic Acid and Melatonin
• Creatine phosphate acts as a high-energy compound, offering a readily accessible reservoir of high-energy phosphates
• Dopamine, norepinephrine, and epinephrine belong to the category of biologically active amines known as catecholamines
• The initial reaction and the last three steps in the formation of porphyrins occur in mitochondria, whereas the intermediate steps of the biosynthetic pathway occur in the cytosol
• Norepinephrine is not solely produced in the brain; it is also synthesized in the adrenal medulla
• Creatine phosphate's ability to transfer its phosphate group reversibly to ADP helps in replenishing ATP levels during the initial moments of intense muscular activity
• Glutathione (GSH) is a vital antioxidant found in cells throughout the body
• Creatine is derived from glycine and the guanidino group of arginine, along with a methyl group from S-adenosyl methionine (SAM)
• Glycine is the precursor of Heme, Purines, Creatine, Glutathione
• Glutathione is composed of three amino acids: glutamine, cysteine, and glycine
• Epinephrine, although synthesized in the adrenal medulla, is also known as adrenaline and is another catecholamine produced in this gland
• Catecholamines undergo deactivation through oxidative deamination, a process facilitated by monoamine oxidase (MAO)