| active methionine | S-(5'-deoxy-5'-adenosyl)-l-methionine;condensation product of adenosine and l-methionine involving replacement of the -OPO3H2 of adenylic acid by -S+ (CH3)CH2CH2CH(NH3+)CO 2 of methionine; a sulfonium compound bearing a methyl group that is transferred in transmethylation reactions. See: methionine adenosyltransferase. Synonym: active methionine. Acronym: SAM (05 Mar 2000) |
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| methionine | <biochemistry> Contains the SCH3 group that can act as a methyl donor (see S adenosyl methionine). Common in proteins but at low frequency. The met x linkage is subject to specific cleavage by cyanogen bromide. See: formyl peptides. (18 Nov 1997) |
| methionine acetyltransferase | <enzyme> Catalyses the amino-terminal acetylation Registry number: EC 2.3.1.- Synonym: methionine n(alpha)-acetyltransferase (26 Jun 1999) |
| methionine-activating enzyme | <enzyme> An enzyme that catalyses the synthesis of s-adenosylmethionine from methionine and ATP. Chemical name: ATP:L-methionine S-adenosyltransferase Registry number: EC 2.5.1.6 (12 Dec 1998) |
| methionine adenosyltransferase | <enzyme> An enzyme that catalyses the synthesis of s-adenosylmethionine from methionine and ATP. Chemical name: ATP:L-methionine S-adenosyltransferase Registry number: EC 2.5.1.6 (12 Dec 1998) |
| methionine decarboxylase | <enzyme> From fern dryopteris filix-mas; pyridoxal 5'-phosphate required for activity; converts methionine to 3-(methylthio)propionaldehyde Registry number: EC 4.1.1.57 Synonym: l-methionine decarboxylase (26 Jun 1999) |
| methionine malabsorption syndrome | <syndrome> An inherited disorder in which there is an inability to absorb l-methionine from the gut. (05 Mar 2000) |
| methionine puddle | <biochemistry> A term used to describe a region of a protein surface composed of a cluster of methionine side chains. Proposed as the active hydrophobic site of calmodulin and also of signal recognition particle (SRP). The concept is of a highly fluid hydrophobic patch. (18 Nov 1997) |
| methionine S-methyltransferase | <enzyme> Catalyses synthesis of s-methylmethionine from l-methionine and s-adenosylmethionine Registry number: EC 2.1.1.12 Synonym: s-adenosyl-l-methionine - l-methionine s-methyltransferase (26 Jun 1999) |
| methionine sulfoxide reductase | <enzyme> Do not confuse with msra gene product from staphylococcus Registry number: EC 1.- Synonym: msra gene product, e. Coli, peptide methionine sulfoxide reductase, peptide msra gene product (26 Jun 1999) |
| methionine sulfoxime | A toxic derivative of methionine formed when proteins containing it are treated with nitrogen chloride to give -SO(NH)CH3 in place of -SCH3. (05 Mar 2000) |
| methionine sulfoximine | <chemical> Chemical name: Butanoic acid, 2-amino-4-(S-methylsulfonimidoyl)- (12 Dec 1998) |
| methionine synthase | Tetrahydropteroylglutamate methyltransferase; methionine-homocysteine methyltransferase;an enzyme that catalyses the reaction of N5-methyltetrahydrofolate with l-homocysteine to form tetrahydrofolate and l-methionine; a cobalamin-requiring enzyme; a deficiency of this enzyme results in an accumulation of l-homocysteine and neurological abnormalities. Synonym: tetrahydrofolate methyltransferase. (05 Mar 2000) |
| methionine-trna ligase | <enzyme> An enzyme that activates methionine with its specific transfer RNA. Chemical name: L-Methionine:tRNA(Met) ligase (AMP-forming) Registry number: EC 6.1.1.10 (12 Dec 1998) |
| cytochrome C-methionine methyltransferase | <enzyme> Forms s-methylmethionine Registry number: EC 2.1.1.- Synonym: cyt c-met methyltransferase (26 Jun 1999) |