1.0 2020-03-18 23:23:18 UTC 2022-12-13 23:36:24 UTC CDB000060 Methionine Methionine, l-methionine abbreviated Met or M, is one of 9 essential amino acids (meaning the body cannot synthesize it; it must be obtained from the diet) required for protein synthesis and for normal growth and development of humans, other mammals, and avian species. It is a white crystalline powder with a mild acidic and sulfurous taste. It is an intermediate in transmethylation reactions, serving as the major methyl group donor for DNA and RNA intermediates. Methionine is a methyl acceptor for 5-methyltetrahydrofolate-homocysteine methyltransferase (methionine synthase), the only reaction that allows for the recycling of this form of folate and is also a methyl acceptor for the catabolism of betaine. Methionine is the metabolic precursor for cysteine where the sulfur atom from methionine is transferred to cysteine (PMID: 16702340). Methionine is an amino acid found in cannabis plants (PMID: 6991645). Methionine is one of 4 sulfur amino acids (SAA) that also include cysteine, taurine and homocysteine (with the latter two not incorporated into proteins). The WHO recommends that healthy adults consume 13 mg/kg per 24 h of normal SAA and roughly double this amount in artificial nutrition regimens. However, in disease or after trauma, SAA requirements may vary. SAA supplementation exceeding 2-3 times the minimum recommended daily intake can be considered safe except in specific cases of congenital enzyme deficiency, prematurity, or diminished liver function where hypermethioninemia or hyperhomocysteinemia may occur. Apart from acetaminophen poisoning, the usefulness of SAA supplementation is not yet established (PMID: 16702341). When present in high levels, methionine can act as an atherogen which is a compound that causes atherosclerosis and cardiovascular disease. Methionine is a precursor of homocysteine. Acute doses of methionine can lead to acute increases in plasma homocysteine, which has been used as an indicator of susceptibility to cardiovascular disease. Longer-term studies in adults have indicated that methionine intakes higher than 5 times the normal amount resulted in elevated homocysteine levels. Rodents fed high levels of methionine developed atherosclerotic plaques independently of homocysteine levels (PMID: 26647293). A similar study in Finnish men showed that high dietary methionine increased the risk of acute coronary events in middle-aged men (PMID: 16487911). These effects of methionine on homocysteine and vascular function are moderated by supplements of vitamins B-6, B-12, C, and folic acid (PMID: 16702346). Methionine is also a metabotoxin, which is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Chronically high levels of methionine are associated with at least ten inborn errors of metabolism, including cystathionine beta-synthase deficiency, glycine N-methyltransferase deficiency, homocystinuria, tyrosinemia, galactosemia, homocystinuria-megaloblastic anemia due to defects in cobalamin metabolism, methionine adenosyltransferase deficiency, methylenetetrahydrofolate reductase deficiency, and S-adenosylhomocysteine (SAH) hydrolase deficiency (PMID: 16702350). Chronically elevated levels of methionine in infants can lead to intellectual disability and other neurological problems, delays in motor skills, sluggishness, muscle weakness, and liver problems. Many individuals with these metabolic disorders tend to develop cardiovascular disease later in life. Methionine is known to exacerbate psychopathological symptoms in schizophrenic patients, with no effects on healthy subjects. (2R)-2-Amino-4-(methylsulfanyl)butanoic acid (R)-2-Amino-4-(methylthio)butanoic acid (R)-Methionine D-2-Amino-4-(methylthio)butyric acid D-Methionin MED (2R)-2-Amino-4-(methylsulfanyl)butanoate (2R)-2-Amino-4-(methylsulphanyl)butanoate (2R)-2-Amino-4-(methylsulphanyl)butanoic acid (R)-2-Amino-4-(methylthio)butanoate D-2-Amino-4-(methylthio)butyrate L-Isomer methionine L-Methionine Pedameth Liquimeth Methionine, L isomer Methionine, L-isomer Methionine C5H11NO2S 149.21 149.051 (2R)-2-amino-4-(methylsulfanyl)butanoic acid D-methionine 348-67-4 CSCC[C@@H](N)C(O)=O InChI=1S/C5H11NO2S/c1-9-3-2-4(6)5(7)8/h4H,2-3,6H2,1H3,(H,7,8)/t4-/m1/s1 FFEARJCKVFRZRR-SCSAIBSYSA-N belongs to the class of organic compounds known as methionine and derivatives. Methionine and derivatives are compounds containing methionine or a derivative thereof resulting from reaction of methionine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. Methionine and derivatives Organic compounds Organic acids and derivatives Carboxylic acids and derivatives Amino acids, peptides, and analogues Aliphatic acyclic compounds Amino acids Carbonyl compounds Carboxylic acids D-alpha-amino acids Dialkylthioethers Hydrocarbon derivatives Monoalkylamines Monocarboxylic acids and derivatives Organic oxides Organopnictogen compounds Sulfenyl compounds Thia fatty acids Aliphatic acyclic compound Alpha-amino acid Amine Amino acid Carbonyl group Carboxylic acid D-alpha-amino acid Dialkylthioether Fatty acid Fatty acyl Hydrocarbon derivative Methionine or derivatives Monocarboxylic acid or derivatives Organic nitrogen compound Organic oxide Organic oxygen compound Organonitrogen compound Organooxygen compound Organopnictogen compound Organosulfur compound Primary aliphatic amine Primary amine Sulfenyl compound Thia fatty acid Thioether D-alpha-amino acid Other amino acids methionine melting_point 281 °C Wikipedia logp -1.85 ALOGPS logs -0.80 ALOGPS logp -2.2 ChemAxon pka_strongest_acidic 2.53 ChemAxon pka_strongest_basic 9.5 ChemAxon iupac (2R)-2-amino-4-(methylsulfanyl)butanoic acid ChemAxon average_mass 149.21 ChemAxon mono_mass 149.051 ChemAxon smiles CSCC[C@@H](N)C(O)=O ChemAxon formula C5H11NO2S ChemAxon inchi InChI=1S/C5H11NO2S/c1-9-3-2-4(6)5(7)8/h4H,2-3,6H2,1H3,(H,7,8)/t4-/m1/s1 ChemAxon inchikey FFEARJCKVFRZRR-SCSAIBSYSA-N ChemAxon polar_surface_area 63.32 ChemAxon refractivity 37.59 ChemAxon polarizability 15.46 ChemAxon rotatable_bond_count 4 ChemAxon acceptor_count 3 ChemAxon donor_count 2 ChemAxon physiological_charge 0 ChemAxon formal_charge 0 ChemAxon number_of_rings 0 ChemAxon bioavailability 1 ChemAxon rule_of_five Yes ChemAxon ghose_filter Yes ChemAxon veber_rule Yes ChemAxon mddr_like_rule Yes ChemAxon C00855 DB02893 16867 84815 CPD-218 Methionine Ball RO, Courtney-Martin G, Pencharz PB: The in vivo sparing of methionine by cysteine in sulfur amino acid requirements in animal models and adult humans. J Nutr. 2006 Jun;136(6 Suppl):1682S-1693S. doi: 10.1093/jn/136.6.1682S. 16702340 Turner CE, Elsohly MA, Boeren EG: Constituents of Cannabis sativa L. XVII. A review of the natural constituents. J Nat Prod. 1980 Mar-Apr;43(2):169-234. doi: 10.1021/np50008a001. 6991645 van de Poll MC, Dejong CH, Soeters PB: Adequate range for sulfur-containing amino acids and biomarkers for their excess: lessons from enteral and parenteral nutrition. J Nutr. 2006 Jun;136(6 Suppl):1694S-1700S. doi: 10.1093/jn/136.6.1694S. 16702341 Selhub J, Troen AM: Sulfur amino acids and atherosclerosis: a role for excess dietary methionine. Ann N Y Acad Sci. 2016 Jan;1363:18-25. doi: 10.1111/nyas.12962. Epub 2015 Dec 8. 26647293 Virtanen JK, Voutilainen S, Rissanen TH, Happonen P, Mursu J, Laukkanen JA, Poulsen H, Lakka TA, Salonen JT: High dietary methionine intake increases the risk of acute coronary events in middle-aged men. Nutr Metab Cardiovasc Dis. 2006 Mar;16(2):113-20. doi: 10.1016/j.numecd.2005.05.005. Epub 2005 Nov 2. 16487911 Garlick PJ: Toxicity of methionine in humans. J Nutr. 2006 Jun;136(6 Suppl):1722S-1725S. doi: 10.1093/jn/136.6.1722S. 16702346 Finkelstein JD: Inborn errors of sulfur-containing amino acid metabolism. J Nutr. 2006 Jun;136(6 Suppl):1750S-1754S. doi: 10.1093/jn/136.6.1750S. 16702350