- Efficient biocatalytic processes for highly valuable terminally phosphorylated C5 to C9 D-ketoses
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A green enzymatic strategy for the synthesis of terminally phosphorylated C5 to C9 naturally occurring D-ketose phosphates and analogues was developed using D-fructose-6-phosphate aldolase (FSA) as a catalyst. This enzyme has stereoselectively catalysed aldol reactions between glycolaldehyde phosphate or ribose-5-phosphate as an acceptor substrate and dihydroxyacetone, hydroxyacetone or hydroxybutanone as a donor. Furthermore, D-glycero-d-altro-2-octulose 8-phosphate was obtained using a straightforward one-pot domino biocatalytic system involving FSA, ribulose-5-phosphate epimerase and ribose-5-phosphate isomerase controlling five contiguous asymmetric centres and starting from achiral material.
- Guerard-Helaine,Debacker,Clapes,Szekrenyi,Helaine,Lemaire
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- D-fructose-6-phosphate aldolase in organic synthesis: Cascade chemical-enzymatic preparation of sugar-relafed polyhydroxylated compounds
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Novel aldol addition reactions of dihydroxyacetone (DHA) and hydroxyacetone (HA) to a variety of aldehydes catalyzed by D-fructose-6-phosphate aldolase (FSA) are presented. In a chemical-enzymatic cascade reaction approach, 1-deoxynojirimycin and 1-deoxymannojirimycin were synthesized starting from (R)- and (S)-3-(N-Cbz-amino)-2-hydroxypropanal, respectively. Furthermore, 1,4-dideoxy1,4-imino-D-arabinitol and 1,4,5-trideoxy-1,4-imino-D-arabinitol were prepared from N-Cbz-glycinal, 1 -Deoxy-D-xylulose was also synthesized by using HA as the donor and either 2-benzyloxyethanal or 2-hydroxyethanal as acceptors. In both cases the enzymatic aldol addition reaction was fully stereoselective, but with 2-hydroxyethanal 17% of the epimeric product at C2, 1-deoxy-D-erythro-2-pentulose, was observed due to enolization/epimerization during the isolation steps. It was also observed that D-(-)-threose is a good acceptor substrate for FSA, opening new synthetic possibilities for the preparation of important novel complex carbohydrate-related compounds from aldoses. To illustrate this, 1-deoxy-D-ido-hept-2-ulose was obtained stereoselectively by the addition of HA to D-(-)-threose, catalyzed by FSA. It was found that the reaction performance depended strongly on the donor substrate, HA being the one that gave the best conversions to the aldol adduct. The examples presented in this work show the valuable synthetic potential of FSA for the construction of chiral complex polyhydroxylated sugar-type structures.
- Concia, Alda Lisa,Lozano, Caries,Castillo, Jose A.,Parella, Teodor,Joglar, Jesus,Clapes, Pere
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experimental part
p. 3808 - 3816
(2010/01/16)
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- 5-hydroxypentane-2,3-dione (Laurencione), a bacterial metabolite of 1- deoxy-D-threo-pentulose
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Cell-free systems from the bacteria Escherichia coli and Klebsiella planticola that were incubated with 13C labeled pyruvate and D- glyceraldehyde synthesized 5-hydroxypentane-2,3-dione (laurencione) along with 1-deoxy-D-threo-pentulose (1-deoxy-D-xylulose). Both compounds showed identical labeling patterns, indicating that the C5 skeletons were derived from the condensation of (hydroxyethyl)thiamin on D-glyceraldehyde. Conversion of [5,5-2H2]deoxyxylulose into laurencione by a cell-free system from E. coli showed that the α-dione is obtained from the pentulose by water elimination.
- Putra, Surya Rosa,Charon, Lionel,Danielsen, Knut,Pale-Grosdemange, Catherine,Lois, Luisa-Maria,Campos, Narciso,Boronat, Albert,Rohmer, Michel
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p. 6185 - 6188
(2007/10/03)
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- Rare keto-aldoses from enzymatic oxidation: Substrates and oxidation products of pyranose 2-oxidase
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Pyranose oxidases are known to oxidise D-glucose, D-xylose and L- sorbose to keto-aldoses, biochemically interesting compounds that may also be used for synthetic purposes in a variety of reactions. In this study pyranose oxidase from the basidiomycete Peniophora gigantea was investigated, and it was found that this enzyme is able to oxidise a broad variety of substrates very effectively. In analogy to its natural mode of action, most substrates are oxidised regioselectively in position 2. Certain compounds, however, are converted into 3-keto derivatives, and the enzyme even exhibits transfer potential, that is, disscharides are formed from β-glycosides of higher alcohols. Substrates that may be oxidised at C-2 in yields between 40-98% are D-allose, D-galactose, 6-deoxy-D-glucose, D-gentiobiose, α-D-glucopyranosyl fluoride and the very interesting 3-deoxy-D-glucose. 1,5-Anhydro-D-glucitol (1-deoxy-D-glucose) is very effectively oxidised in position 2 in 98% yield and additionally gives a product of dioxidation at C-2 and C-3 upon prolonged reaction time Selective oxidation at C-3 was found for 2-deoxy-D-glucose in very good yields and for methyl β-D-gluco- and methyl β-galactopyranoside in lower yields. All oxidation products were unequivocally characterised by NMR spectroscopy and/or chemical derivatisation. In addition, the kinetic data of the enzymatic reactions were determined for all substrates. On the basis of these data and the structural characteristics of the substrates, a model for the minimal structural requirements of the enzyme-substrate interaction is suggested. The enzyme presumably uses two different binding modes for the regioselective C-2 and the C-3 oxidations, which are described.
- Freimund, Stefan,Huwig, Alexander,Giffhorn, Friedrich,Koepper, Sabine
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p. 2442 - 2455
(2007/10/03)
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