title: Biosynthesis of avenacins and phytosterols in roots of Avena sativa cv. Image.
abstract: In keeping with the proposal that avenacin biosynthesis is restricted to the tips of primary roots of oat seedlings, the incorporation of radioactivity from R-[2-(14)C]mevalonic acid (MVA) into avenacins and beta-amyrin by serial sections of primary roots was found to be more-or-less restricted to root tip sections. Squalene synthase (SQS) (EC 2.5.1.21) and 2,3-oxidosqualene:beta-amyrin cyclase (OS beta AC) (EC 5.4.99) were also most active in these sections. The incorporation of radiolabel from R-[2-(14)C]MVA into cycloartenol and 24-methylene cycloartanol by, and the 2,3-oxidosqualene:cycloartenol cyclase (OSCC) (EC 5.4.99) activity in, the various serial sections were consistent with phytosterol biosynthesis occurring in all the sections of the root with some tailing-off in the rate of synthesis in the more distal sections.
authors.affiliation: Department of Biological Sciences, University of Hull, UK. miranda.trojanowska@bbsrc.ac.uk
authors.forename: M R
authors.initials: MR
authors.lastname: Trojanowska
authors.forename: A E
authors.initials: AE
authors.lastname: Osbourn
authors.forename: M J
authors.initials: MJ
authors.lastname: Daniels
authors.forename: D R
authors.initials: DR
authors.lastname: Threlfall
mesh_terms: D018554:Avena / Q000201:enzymology / Q000378:metabolism*; D002240:Carbohydrate Sequence; D002250:Carbon Radioisotopes; D013186:Farnesyl-Diphosphate Farnesyltransferase / Q000378:metabolism; D019751:Intramolecular Transferases / Q000378:metabolism; D008798:Mevalonic Acid / Q000378:metabolism; D010840:Phytosterols / Q000096:biosynthesis*; D018517:Plant Roots / Q000201:enzymology / Q000378:metabolism; D012503:Saponins / Q000096:biosynthesis*
chemical_list: D002250:Carbon Radioisotopes; D010840:Phytosterols; D012503:Saponins; C091460:avenacin A 1; D013186:Farnesyl-Diphosphate Farnesyltransferase; D019751:Intramolecular Transferases; C039924:2,3-oxidosqualene-beta-amyrin-cyclase; D008798:Mevalonic Acid