Isolation and functional characterization of a novel plastidic hexokinase from Nicotiana tabacum.
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.
Giese
Jens-Otto
JO
Institut für Pflanzengenetik und Kulturpflanzenforschung, Corrensstr. 3, 06466 Gatersleben, Germany.
Herbers
Karin
K
Hoffmann
Manuela
M
Klösgen
Ralf Bernd
RB
Sonnewald
Uwe
U
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*
D017931:DNA Primers; D018076:DNA, Complementary; D006593:Hexokinase