The l-isomer is an intermediate in the conversion of l-methionine to l-cysteine; cleaved by cystathionases.
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cys·ta·thi·o·nine .sis-tə-'thī-ə-.nēn n a sulfur-containing amino acid C7H14N2O4S formed as an intermediate in the conversion of methionine to cysteine
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cys·ta·thi·o·nine (sis″tə-thiґo-nēn) an unsymmetrical thio-ether of homocysteine and serine that serves as an intermediate in the transfer of a sulfur atom from methionine to cysteine.Medical dictionary. 2011.