Formation of 1-Deoxy-ketoses by Pyruvate Dehydrogenase and Acetoin Dehydrogenase

Yokota, Akira; Sasajima, Ken-ichi

doi:10.1080/00021369.1986.10867789

Cited by 20 publications

(29 citation statements)

References 8 publications

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“…In preliminary experiments, we detected the conversion of [1,[2][3][4][5][6][7][8][9][10][11][12][13][14] C 2 ]1-deoxy-d-xylulose into a phosphorylated product by radiochromatography. The phosphorylated product had an R f value of 0.35, whereas the R f value of the substrate was 0.71.…”

Section: R E S U L T Smentioning

confidence: 99%

“…It had already been shown in 1986 that 1-deoxy-dxylulose is formed in vitro by pyruvate dehydrogenase of E. coli and B. subtilis from pyruvate and glyceraldehyde [12]. More recent studies established that the early steps of the alternative isoprenoid pathway proceed via phosphoric acid esters rather than unphosphorylated carbohydrates.…”

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confidence: 99%

“…The preparation of [3,4,[5][6][7][8][9][10][11][12][13] C 3 ]1-deoxy-d-xylulose 5-phosphate will be described elsewhere.…”

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Phosphorylation of 1‐deoxy‐D‐xylulose by D‐xylulokinase of Escherichia coli

Wungsintaweekul¹,

Herz

Hecht

et al. 2001

European Journal of Biochemistry

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1‐deoxy‐d‐xylulose 5‐phosphate serves as a precursor for the biosynthesis of the vitamins thiamine and pyridoxal and for the formation of isopentenyl pyrophosphate and dimethylallyl pyrophosphate via the nonmevalonate pathway of terpenoid biosynthesis. Earlier studies had shown that Escherichia coli incorporates unphosphorylated 1‐deoxy‐d‐xylulose into the terpenoid side chain of ubiquinones with high efficacy. We show that d‐xylulokinase of E. coli (EC 2.7.1.17) catalyzes the phosphorylation of 1‐deoxy‐d‐xylulose at the hydroxy group of C‐5 at a rate of 1.6 µmol·mg min−1. This reaction constitutes a potential salvage pathway for the generation of 1‐deoxy‐d‐xylulose 5‐phosphate from exogenous or endogenous 1‐deoxy‐d‐xylulose as starting material for the biosynthesis of terpenoids, thiamine and pyridoxal.

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confidence: 99%

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Phosphorylation of 1‐deoxy‐D‐xylulose by D‐xylulokinase of Escherichia coli

Wungsintaweekul¹,

Herz

Hecht

et al. 2001

European Journal of Biochemistry

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“…The E1 component (pyruvate decarboxylase) of the pyruvate dehydrogenase complex was identified to catalyze the decarboxylation of pyruvate and the condensation of the enzyme-bound hydroxyethyl-thiamine diphosphate with glyceraldehydes (Yokota and Sasajima, 1986). In plants, the localization of this complex is mitochondrial and plastidial (Tovar-Méndez et al, 2003); however, the physiological relevance or even presence of these secondary activities remains obscure.…”

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A Cytosolic Arabidopsis d-Xylulose Kinase Catalyzes the Phosphorylation of 1-Deoxy-d-Xylulose into a Precursor of the Plastidial Isoprenoid Pathway

et al. 2006

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Plants are able to integrate exogenous 1-deoxy-D-xylulose (DX) into the 2C-methyl-D-erythritol 4-phosphate pathway, implicated in the biosynthesis of plastidial isoprenoids. Thus, the carbohydrate needs to be phosphorylated into 1-deoxy-D-xylulose 5-phosphate and translocated into plastids, or vice versa. An enzyme capable of phosphorylating DX was partially purified from a cell-free Arabidopsis (Arabidopsis thaliana) protein extract. It was identified by mass spectrometry as a cytosolic protein bearing D-xylulose kinase (XK) signatures, already suggesting that DX is phosphorylated within the cytosol prior to translocation into the plastids. The corresponding cDNA was isolated and enzymatic properties of a recombinant protein were determined. In Arabidopsis, xylulose kinases are encoded by a small gene family, in which only two genes are putatively annotated. The additional gene is coding for a protein targeted to plastids, as was proved by colocalization experiments using green fluorescent protein fusion constructs. Functional complementation assays in an Escherichia coli strain deleted in XK revealed that the cytosolic enzyme could exclusively phosphorylate xylulose in vivo, not the enzyme that is targeted to plastids. XK activities could not be detected in chloroplast protein extracts or in proteins isolated from its ancestral relative Synechocystis sp. PCC 6803. The gene encoding the plastidic protein annotated as ''xylulose kinase'' might in fact yield an enzyme having different phosphorylation specificities. The biochemical characterization and complementation experiments with DX of specific Arabidopsis knockout mutants seedlings treated with oxo-clomazone, an inhibitor of 1-deoxy-D-xylulose 5-phosphate synthase, further confirmed that the cytosolic protein is responsible for the phosphorylation of DX in planta.In plants, the biosynthesis of the active isoprene units (D 2 -and D 3

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“…4PHT and DX (or DXP) were shown to be in vivo precursors of PLP (10,11,13,33). The steps leading to DX (or DXP) are not exactly known (36,37), and DX (or DXP) is thought to be a precursor of thiamine and possibly riboflavin (5,6,29,30). The postulated role of PdxJ and PdxA in pyridine ring closure was based solely on the growth properties of mutants (see text) (10,17).…”

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confidence: 99%