L

L-Methionine

IUPAC: (2S)-2-amino-4-methylsulfanylbutanoic acid

C5H11NO2S Organic Compounds CAS 63-68-3
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Quick Reference
Formula / NotationC5H11NO2S
CAS Number63-68-3
Molecular Weight149.21
Melting Point536 to 540 °F decomposes 541.4-543.2 °F (NTP, 1992)
Boiling Pointsublimes at 367 °F (NTP, 1992)
Density1.178 at 68 °F (NTP, 1992) - Denser than water; will sink
SolubilitySoluble (NTP, 1992)
AppearanceMinute hexagonal plates from dilute alcohol. (NTP, 1992)
Also Known As(2S)-2-amino-4-methylsulfanylbutanoic acid; 63-68-3; methionine; h-Met-oh; (S)-2-Amino-4-(methylthio)butanoic acid; Cymethion; L-(-)-Methionine; S-Methionine; L-Methioninum; Neo-methidin
CategoryOrganic Compounds

What is L-Methionine?

L-methionine is the L-enantiomer of methionine. It has a role as a micronutrient, a nutraceutical, an antidote to paracetamol poisoning, a mouse metabolite and a human metabolite. It is a L-alpha-amino acid, a methionine, an aspartate family amino acid and a proteinogenic amino acid. It is a conjugate base of a L-methioninium. It is a conjugate acid of a L-methioninate. It is an enantiomer of a D-methionine. It is a tautomer of a L-methionine zwitterion.

Formula & Notation

C5H11NO2S

IUPAC Name: (2S)-2-amino-4-methylsulfanylbutanoic acid

Other Names / Synonyms: (2S)-2-amino-4-methylsulfanylbutanoic acid; 63-68-3; methionine; h-Met-oh; (S)-2-Amino-4-(methylthio)butanoic acid; Cymethion; L-(-)-Methionine; S-Methionine; L-Methioninum; Neo-methidin

Properties & Characteristics

Appearance: Minute hexagonal plates from dilute alcohol. (NTP, 1992). Molecular formula: C5H11NO2S. Molecular weight: 149.21 g/mol. Boiling point: sublimes at 367 °F (NTP, 1992). Melting point: 536 to 540 °F decomposes 541.4-543.2 °F (NTP, 1992). Density: 1.178 at 68 °F (NTP, 1992) - Denser than water; will sink. Solubility: Soluble (NTP, 1992). Vapor pressure: 0.00000052 [mmHg]. LogP: -1.9.

Physical Data

PropertyValue
Melting Point536 to 540 °F decomposes 541.4-543.2 °F (NTP, 1992)
Boiling Pointsublimes at 367 °F (NTP, 1992)
Density1.178 at 68 °F (NTP, 1992) - Denser than water; will sink
Molecular Weight149.21
SolubilitySoluble (NTP, 1992)
AppearanceMinute hexagonal plates from dilute alcohol. (NTP, 1992)

Uses & Applications

Used as an industrial feedstock, solvent, pharmaceutical intermediate, flavoring agent, or chemical building block.

Safety Information

Flammable or irritant. Many organic compounds are flammable liquids or vapours. Keep away from ignition sources. Consult SDS for specific hazard data.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term L-Methionine
Formula C5H11NO2S
CAS Number 63-68-3
Molecular Weight 149.21
Synonyms (2S)-2-amino-4-methylsulfanylbutanoic acid; 63-68-3; methionine; h-Met-oh; (S)-2-Amino-4-(methylthio)butanoic acid; Cymethion; L-(-)-Methionine; S-Methionine; L-Methioninum; Neo-methidin

Frequently Asked Questions

L-methionine is the L-enantiomer of methionine. It has a role as a micronutrient, a nutraceutical, an antidote to paracetamol poisoning, a mouse metabolite and a human metabolite. It is a L-alpha-amino acid, a methionine, an aspartate family amino acid and a proteinogenic amino acid. It is a conjugate base of a L-methioninium. It is a conjugate acid of a L-methioninate. It is an enantiomer of a D-methionine. It is a tautomer of a L-methionine zwitterion.

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Editorial standards: Chemical data is sourced from peer-reviewed literature, CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA, and IAEA. For educational purposes only — always consult official SDS documentation and qualified professionals before handling chemicals.