L-Methionine Derived Secondary Products

L-Methionine, (S)- -amino-y-methylthiobutyric acid, is one of the most important sulfur-containing primary amino acids. Secondary products derived from L-methionine either contain still the more or less complete methionine skeleton [cf. the formulas of S-adenosyl-L-methionine, azetidine-2-carboxylic acid, 1-aminocyclopropane carboxylic acid (Fig. 192), spermidine and spermine (Fig. 193)], or only the methyl group of L-methionine (most 0-, iV-, S- and C-methylated secondary products). The sulfur-containing derivatives possess either a sulfide (—S—) or a sulfonium (—S+—) group. 

Secondary products derived from L-methionine occur in microorganisms, plants, and animals. 

S-Adenosy I methionine, 0-,N-S- and C-methylated compounds, acetidine-2-carboxylic add, 1-amino-cycLopropane carboxylic acid, spermidine, thiamine 

1 Homoserine kinase 2 homoserine acyltransferase 3 0-succinylhomoserine (thiol)-lyase 4 cystathionine -lyase 5 tetrahydropteroylglutamate methyltransferase 

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S-substituted cysteine derivatives and sulfoxides (D 11.2) L-Methionine-derived secondary products (D 12)... 

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