Gast ::
| Hauptseite > Publikationsdatenbank > Elucidation of the Final Reactions of DIMBOA-Glucoside Biosysnthesis in Maize: Characterization of Bx6 and Bx71[W][OA] |
| Hauptseite > Publikationsdatenbank > Elucidation of the Final Reactions of DIMBOA-Glucoside Biosysnthesis in Maize: Characterization of Bx6 and Bx71[W][OA] |
| Journal Article | PreJuSER-62913 |
; ; ; ; ; ; ; ; ; ; ;
2008
JSTOR
Rockville, Md.: Soc.
This record in other databases: 
Please use a persistent id in citations: doi:10.1104/pp.107.111237
Abstract: Benzoxazinoids were identified in the early 1960s as secondary metabolites of the grasses that function as natural pesticides and exhibit allelopathic properties. Benzoxazinoids are synthesized in seedlings and stored as glucosides (glcs); the main aglucone moieties are 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA) and 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA). The genes of DIBOA-glc biosynthesis have previously been isolated and the enzymatic functions characterized. Here, the enzymes for conversion of DIBOA-glc to DIMBOA-glc are identified. DIBOA-glc is the substrate of the dioxygenase BENZOXAZINLESS6 (BX6) and the produced 2,4,7-trihydroxy-2H-1,4-benzoxazin-3-(4H)-one-glc is metabolized by the methyltransferase BX7 to yield DIMBOA-glc. Both enzymes exhibit moderate K(m) values (below 0.4 mm) and k(cat) values of 2.10 s(-1) and 0.25 s(-1), respectively. Although BX6 uses a glucosylated substrate, our localization studies indicate a cytoplasmic localization of the dioxygenase. Bx6 and Bx7 are highest expressed in seedling tissue, a feature shared with the other Bx genes. At present, Bx6 and Bx7 have no close relatives among the members of their respective gene families. Bx6 and Bx7 map to the cluster of Bx genes on the short arm of chromosome 4.
Keyword(s): Benzoxazines: metabolism (MeSH) ; Chromosomes, Plant (MeSH) ; Cytoplasm: enzymology (MeSH) ; Genes, Plant (MeSH) ; Glucosides: biosynthesis (MeSH) ; Glucosides: metabolism (MeSH) ; Molecular Sequence Data (MeSH) ; Multigene Family (MeSH) ; Phylogeny (MeSH) ; Protein O-Methyltransferase: genetics (MeSH) ; Protein O-Methyltransferase: metabolism (MeSH) ; Seedling: enzymology (MeSH) ; Zea mays: enzymology (MeSH) ; Zea mays: genetics (MeSH) ; 2,4-dihydroxy-1,4-benzoxazin-3-one ; 2-O-glucopyranosyl-4-hydroxy-7-methoxy-1,4-benzoxazin-3-one ; Benzoxazines ; Glucosides ; 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one ; Protein O-Methyltransferase ; J
|
The record appears in these collections: |
