title: Unraveling the methionine-cephalosporin puzzle in Acremonium chrysogenum.
abstract: Methionine has long been known as the major stimulant of the formation of cephalosporin C in Acremonium chrysogenum. Enzymatic and genetic studies of methionine have revealed that it induces four of the enzymes of cephalosporin-C biosynthesis at the level of transcription. It is also converted to cysteine, one of three precursors of cephalosporin C, by cystathionine-gamma-lyase. The main effect of methionine on cephalosporin production results from its regulatory role, which can be duplicated by the non-sulfur analog norleucine. Eliminating cystathionine-gamma-lyase prevents the enhancing precursor effect of methionine on cephalosporin-C production, and cystathionine-gamma-lyase overproduction in moderate doses increases cephalosporin-C formation.
authors.affiliation: Area of Microbiology, University of León, Spain. degjmm@unileon.es
authors.forename: Juan F
authors.initials: JF
authors.lastname: Martín
authors.forename: Arnold L
authors.initials: AL
authors.lastname: Demain
mesh_terms: D000164:Acremonium / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D002511:Cephalosporins / Q000096:biosynthesis*; D003001:Cloning, Molecular; D003545:Cysteine / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects*; D008715:Methionine / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000235:genetics* / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D002511:Cephalosporins; D009097:Multienzyme Complexes; D008715:Methionine; D003545:Cysteine