Methionine

related topics
{acid, form, water}
{food, make, wine}
{system, computer, user}
{style, bgcolor, rowspan}

281 °C decomp.

Methionine (pronounced /mɛˈθaɪ.ɵniːn/, /mɛˈθaɪ.ɵnɪn/; abbreviated as Met or M)[3] is an α-amino acid with the chemical formula HO2CCH(NH2)CH2CH2SCH3. This essential amino acid is classified as nonpolar.

Contents

Function

Together with cysteine, methionine is one of two sulfur-containing proteinogenic amino acids. Its derivative S-adenosyl methionine (SAM) serves as a methyl donor. Methionine is an intermediate in the biosynthesis of cysteine, carnitine, taurine, lecithin, phosphatidylcholine, and other phospholipids. Improper conversion of methionine can lead to atherosclerosis.[4]

This amino acid is also used by plants for synthesis of ethylene. The process is known as the Yang Cycle or the methionine cycle.

Methionine is one of only two amino acids encoded by a single codon (AUG) in the standard genetic code (tryptophan, encoded by UGG, is the other). The codon AUG is also the "Start" message for a ribosome that signals the initiation of protein translation from mRNA. As a consequence, methionine is incorporated into the N-terminal position of all proteins in eukaryotes and archaea during translation, although it is usually removed by post-translational modification. In bacteria, the derivative N-formylmethionine is used as the initial amino acid.

Full article ▸

related documents
Borate
Acetonitrile
Exon
Vesicle (biology)
Asparagine
Amyl alcohol
Millerite
Radiogenic
Piperidine
Corundum
DNA ligase
Proton pump
Actinoid
Haematoxylin
Potash
Electrochemical cell
Flavin
Primary nutritional groups
Metabolic pathway
Quaternary structure
Ammonium
Aqueous solution
Butanol
Messenger RNA
Butane
Peptide nucleic acid
Crystal
Synthetic radioisotope
Synthetic element
Ostwald process