title: S-adenosylmethionine-dependent enzyme activation.
abstract: S-Adenosylmethionine (SAM)-dependent activations of pyruvate formate-lyase, lysine 2,3-aminomutase and cobalamin-dependent methionine synthase are discussed. In each case, cleavage of SAM is accompanied by the formation of a catalytically active enzyme. The chemistry of activation of these three enzymes falls into three distinct classes: generation of an essential enzyme radical (pyruvate formate-lyase), formation of a catalytically active 5'-deoxyadenosyl radical (lysine 2,3-aminomutase) and reductive methylation to form a required methylcobalamin complex (methionine synthase).
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland, College Park 20742.
authors.forename: J W
authors.initials: JW
authors.lastname: Kozarich
mesh_terms: D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase / Q000378:metabolism*; D000123:Acetyltransferases / Q000378:metabolism*; D000591:Amino Acid Isomerases / Q000378:metabolism*; D004789:Enzyme Activation; D019751:Intramolecular Transferases; D008780:Methyltransferases / Q000378:metabolism*; D012436:S-Adenosylmethionine / Q000502:physiology*
chemical_list: D012436:S-Adenosylmethionine; D008780:Methyltransferases; D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase; D000123:Acetyltransferases; C022560:formate C-acetyltransferase; D000591:Amino Acid Isomerases; D019751:Intramolecular Transferases; C021518:lysine 2,3-aminomutase