METHIONINE (2-amino-4-methylthiobutane to - that, Met; L) CH3SCH2CH2CH(NH2)COOH, mol.m. 149,21; bestsv. crystals with spetsifich. unpleasant smell. For L-, D-and D, L-methionine t.pl. sootv. 280-282, 200-240 and 281 °C (all isomers melt with razl.); for L-methionine and D20sootv D-methionine [a]. +23,7 ° and — 23,7 ° (concentration of 5 g in 100 ml 5 N of NSL); rastvo. in water, it is limited - in ethanol, not rastvo. in alcohols, diethyl ether, acetone, benzene. At 25 °C for L-methionine rka 2,28 (COOH) and 9,21 (NH2); pI 5,74.
On chemical to sv-you methionine-alifatich. a-amino acid. At recovery of methionine by means of HI in prinut. red phosphorus it is formed 2-amino-4-mercaptobutane to - that (gomotsiste-in). In soft conditions methionine is oxidized to metioninsul-foksid; H2O2, HClO4, etc. silnyeokislitel oxidize methionine to metioninsulfon. At synthesis from methionine of peptides for protection of g-methylthiogroup of the rest of methionine it is oxidized to sulphoxide, to-ry upon termination of synthesis of m. it is recovered by mercaptoethanol.
L-methionine-necessary food item for the person and animals (the essential coded amino acid). Meets in all organisms as a part of molekulbelok and peptides, is part of opioid peptidaenkefalin; casein is especially rich with methionine. Methionine plays important role in bio-sintetich. methylation.
Organisms are capable to acquire both L-methionine, and D-methionine. At the same time D-methionine turns in 2-oxo-4-methylthiobutane to - that, edges is aminated with the address of configuration. Methionine biosynthesis: from 2-amino-4-hydroxybutane to - you (homoserine) through gomotsistein; breaks up in organism to 2-oxo-butane to - you or to homoserine.
Emit methionine from casein hydrolyzates. Prom. synthesis is usually carried out from 3-methylthiopropionic aldehyde. In L-methionine PMR range in D2O chemical shifts (in m) 3,865 (A-N); 2,17 (B-N); 2,649 (G-N); 2,141 (E-N).
S-Metilirovanny L-methionine (metioninmetilsulfony-chloride, or active methionine) - vitamin for mammals and the person. L-methionine is applied to enrichment of forages and food and also as lek. Wednesday - in for treatment and the prevention of diseases and toksich. damages of liver, treatment of atherosclerosis; use for synthesis of peptides. Spetsifich. splitting of peptide bonds on the methionine remains when processing by cyanogen bromide is used when determining primary structure of proteins. Kolorimetrich. definition of methionine is based on formation of coloring at action of nitroprussid of Na in the silnoshchelochny environment. For the first time L-methionine is emitted from casein in 1922 by I. Müller. Its world pro-publishing house apprx. 150 tons/year