title: Isolation and functional characterization of a novel plastidic hexokinase from Nicotiana tabacum.
abstract: Due to their central role in sugar metabolism and signalling plant hexokinases have been studied in great detail, however, little is known about the spatial and temporal expression and the sub-cellular distribution of individual hexokinase isoforms. Based on in planta and in vitro studies the recently isolated tobacco hexokinase 2 (Hxk2) could be located in the chloroplast stroma and biochemically characterized. Hxk2 represents the first innerplastidic hexokinase described from higher plants. Promoter studies indicate that Hxk2 is mainly expressed in cells of the vascular starch sheath and xylem parenchyma, in guard cells and root tips. We propose a role for Hxk2 in starch and secondary metabolism in the mentioned tissues.
authors.affiliation: Institut für Pflanzengenetik und Kulturpflanzenforschung, Corrensstr. 3, 06466 Gatersleben, Germany.
authors.forename: Jens-Otto
authors.initials: JO
authors.lastname: Giese
authors.forename: Karin
authors.initials: K
authors.lastname: Herbers
authors.forename: Manuela
authors.initials: M
authors.lastname: Hoffmann
authors.forename: Ralf Bernd
authors.initials: RB
authors.lastname: Klösgen
authors.forename: Uwe
authors.initials: U
authors.lastname: Sonnewald
mesh_terms: D001483:Base Sequence; D003124:Colorimetry; D017931:DNA Primers; D018076:DNA, Complementary; D006593:Hexokinase / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D018087:Plastids / Q000201:enzymology*; D011401:Promoter Regions, Genetic; D021381:Protein Transport; D014026:Nicotiana / Q000201:enzymology*
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D006593:Hexokinase