title: meta-Tyrosine in Festuca rubra ssp. commutata (Chewings fescue) is synthesized by hydroxylation of phenylalanine.
abstract: m-Tyrosine is a non-protein amino acid that is structurally similar to the common protein amino acids p-tyrosine and phenylalanine. Copious amounts of m-tyrosine can be found in root exudates of the fine fescue cultivar, Festuca rubra L. ssp. commutata (Chewings fescue). The phytotoxicity of m-tyrosine may contribute to the allelopathic potential of F. rubra. m-Tyrosine in Euphorbia myrsinites (donkey-tail spurge), was previously shown to be synthesized via transamination of m-hydroxyphenylpyruvate. Here we show that m-tyrosine biosynthesis in F. rubra occurs through direct hydroxylation of phenylalanine in the root tips, perhaps through the activity of a cytochrome P450 enzyme. Hence, E. myrsinites and F. rubra, the only two plant species known to produce m-tyrosine, use distinct biosynthetic pathways that likely arose independently in evolutionary history.
authors.affiliation: Boyce Thompson Institute for Plant Research, 1 Tower Road, Ithaca, NY 14853, USA.
authors.forename: Tengfang
authors.initials: T
authors.lastname: Huang
authors.forename: Ludmila
authors.initials: L
authors.lastname: Rehak
authors.forename: Georg
authors.initials: G
authors.lastname: Jander
mesh_terms: D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D031751:Festuca / Q000737:chemistry* / Q000378:metabolism; D006900:Hydroxylation; D015394:Molecular Structure; D010649:Phenylalanine / Q000737:chemistry / Q000378:metabolism*; D018517:Plant Roots / Q000737:chemistry* / Q000378:metabolism; D014443:Tyrosine / Q000096:biosynthesis* / Q000737:chemistry
chemical_list: D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D014443:Tyrosine; D010649:Phenylalanine; D003577:Cytochrome P-450 Enzyme System; C015566:3-tyrosine