title: [13C]-Specific labeling of 8-2' linked (-)-cis-blechnic, (-)-trans-blechnic and (-)-brainic acids in the fern Blechnum spicant.
abstract: In vivo administration experiments using stable (13C) and radio (14C) labeled precursors established that the optically active 8-2' linked lignans, (-)-cis-blechnic, (-)-trans-blechnic and (-)-trans-brainic acids, were directly derived from L-phenylalanine, cinnamate, and p-coumarate but not either from tyrosine or acetate. The radiochemical time course data suggest that the initial coupling product is (-)-cis-blechnic acid, which is then apparently converted into both (-)-trans-blechnic and (-)-trans-brainic acids in vivo. These findings provide additional evidence for vascular plant proteins engendering distinct but specific phenolic radical-radical coupling modes, i.e., for full control over phenylpropanoid coupling in vivo, whether stereoselective or regiospecific.
authors.affiliation: Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA.
authors.forename: Laurence B
authors.initials: LB
authors.lastname: Davin
authors.forename: Chang-Zeng
authors.initials: CZ
authors.lastname: Wang
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Helms
authors.forename: Norman G
authors.initials: NG
authors.lastname: Lewis
mesh_terms: D002109:Caffeic Acids / Q000737:chemistry / Q000378:metabolism; D002250:Carbon Radioisotopes; D003373:Coumaric Acids / Q000737:chemistry / Q000378:metabolism; D029624:Ferns / Q000737:chemistry*; D017705:Lignans / Q000737:chemistry* / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D010636:Phenols / Q000032:analysis / Q000737:chemistry; D010649:Phenylalanine / Q000737:chemistry / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D002109:Caffeic Acids; D002250:Carbon Radioisotopes; D003373:Coumaric Acids; D017705:Lignans; D010636:Phenols; D010649:Phenylalanine