Synthesis and evaluation of malonate-based inhibitors of phosphosugar-metabolizing enzymes: class II fructose-1,6-bis-phosphate aldolases, type I phosphomannose isomerase, and phosphoglucose isomerase.

In the design of inhibitors of phosphosugar metabolizing enzymes and receptors with therapeutic interest, malonate has been reported in a number of cases as a good and hydrolytically-stable surrogate of the phosphate group, since both functions are dianionic at physiological pH and of comparable size. We have investigated a series of malonate-based mimics of the best known phosphate inhibitors of class II (zinc) fructose-1,6-bis-phosphate aldolases (FBAs) (e.g.

Mannitol Bis-phosphate Based Inhibitors of Fructose 1,6-Bisphosphate Aldolases.

Several 5-O-alkyl- and 5-C-alkyl-mannitol bis-phosphates were synthesized and comparatively assayed as inhibitors of fructose bis-phosphate aldolases (Fbas) from rabbit muscle (taken as surrogate model of the human enzyme) and from Trypanosoma brucei. A limited selectivity was found in several instances. Crystallographic studies confirm that the 5-O-methyl derivative binds competitively with substrate and the 5-O-methyl moiety penetrating deeper into a shallow hydrophobic pocket at the active site.

Glycolytic and non-glycolytic functions of Mycobacterium tuberculosis fructose-1,6-bisphosphate aldolase, an essential enzyme produced by replicating and non-replicating bacilli.

The search for antituberculosis drugs active against persistent bacilli has led to our interest in metallodependent class II fructose-1,6-bisphosphate aldolase (FBA-tb), a key enzyme of gluconeogenesis absent from mammalian cells. Knock-out experiments at the fba-tb locus indicated that this gene is required for the growth of Mycobacterium tuberculosis on gluconeogenetic substrates and in glucose-containing medium. Surface labeling and enzymatic activity measurements revealed that this enzyme was exported to the cell surface of M.

Rational design, synthesis, and evaluation of new selective inhibitors of microbial class II (zinc dependent) fructose bis-phosphate aldolases.

We report the synthesis and biochemical evaluation of several selective inhibitors of class II (zinc dependent) fructose bis-phosphate aldolases (Fba). The products were designed as transition-state analogues of the catalyzed reaction, structurally related to the substrate fructose bis-phosphate (or sedoheptulose bis-phosphate) and based on an N-substituted hydroxamic acid, as a chelator of the zinc ion present in active site. The compounds synthesized were tested on class II Fbas from various pathogenic microorganisms and, by comparison, on a mammalian class I Fba.

Highly Selective Inhibitors of Class II Microbial Fructose Bis-phosphate Aldolases.

We hereby describe the rationale synthesis and biochemical evaluation of the most powerful and selective inhibitors of class II fructose bis-phosphate aldolases so far reported. These inhibitors are of potential therapeutic interest, since the class II enzyme is present exclusively in microorganisms (among which many pathogenic species) and is absent from man, plants, and animals.

Stereocontrol by a pair of epimeric sugar-derived ligands of the coordination sphere of copper(II) complexes.

A pair of novel C3-epimeric sugar-derived ligands (glycoligands) with a neutral N4O donor set was synthesized. Copper(II) complexes of both ligands were obtained and characterized by X-ray crystallography. Cyclic voltammetry, electron paramagnetic resonance, and UV-vis spectroscopies showed similar electronic properties.

Separate synthesis and evaluation of glucitol bis-phosphate and mannitol bis-phosphate, as competitive inhibitors of fructose bis-phosphate aldolases.

We report the first unambiguous syntheses of glucitol-1,6-bis-phosphate and mannitol-1,6-bis-phosphate and their competitive inhibition of various fructose bis-phosphate aldolases.

Synthesis and X-ray crystal structures of two transition metal complexes based on functionalised 1,5-anhydro-2-deoxy-D-galactitol and methyl 2-deoxy-alpha-D-galactopyranoside.

Two new ligands of transition metal cations based on galactose-derived scaffolds were synthesised: 1,5-anhydro-2-deoxy-3,4,6-tri-O-(2-picolyl)-D-galactitol and methyl 2-deoxy-3,4,6-tri-O-(2-picolyl)-alpha-D-galactopyranoside. These ligands permitted the isolation as single crystals of a Co(II) and a Ni(II) complex, respectively. The structures of both complexes were determined by X-ray crystallography showing a coordination sphere including sugar-bound oxygen atoms.

Diaqua[methyl 4-O-benzyl-2,3,6-tri-O-(2-picolyl)-alpha-D-mannopyranoside]cobalt(II) bis(perchlorate) monohydrate: partial coordination of a ligand derived from D-mannose.

The title compound, [Co(C(32)H(35)N(3)O(6))(H2O)2](ClO4)(2).H2O, contains a cationic complex with a novel facultative hexadentate sugar-derived ligand coordinated in a tetradentate fashion to give a CoN(2)O(4) coordination. The partial coordination is imposed by the rigid conformation of the sugar.

New competitive inhibitors of cytosolic (NADH-dependent) rabbit muscle glycerophosphate dehydrogenase.

We report the synthesis and biochemical evaluation of new competitive inhibitors of the cytosolic (NADH-dependent) glycerophosphate dehydrogenase. The best tested compound, phosphono-propionohydroxamic acid, with a Ki of 6 microM, might be of interest as an anti-obesity drug.

Enzymatic synthesis of aldonic acids.

Several aldonic acids (D-mannonic, D-galactonic, D-xylonic, 2-deoxy-D-arabinohexonic (2-deoxy-D-gluconic)) were prepared on a scale of several grams by a simple oxidation catalyzed by glucose oxidase in pure water.

Superoxide dismutase-like activity of cobalt(II) complexes based on a sugar platform.

A SOD-like activity evaluated by a modified McCord-Fridovich test was evidenced for two Co(II) complexes built from "glycoligands" using a sugar platform derived from d-galactose and D-galactal and functionalized by three 2-picolyl groups.

New inhibitors of rabbit muscle triose-phosphate isomerase.

We describe the synthesis and evaluation of three new competitive inhibitors of triose-phosphate isomerase. One of them (phosphoglycoloamidoxime: K(i) = 4.5 microM) is among the best reversible inhibitors so far reported for this enzyme.

Enzymatic synthesis of D-glucosaminic acid from D-glucosamine.

D-glucosaminic acid (2-amino-2-deoxy-D-gluconic acid), a component of bacterial lipopolysaccharides and a chiral synthon, is easily prepared on a multigram scale by air oxidation of D-glucosamine (2-amino-2-deoxy-D-glucose) catalysed by glucose oxidase.

Oxidation of chlorophenols catalyzed by Coprinus cinereus peroxidase with in situ production of hydrogen peroxide.

Degradation of 2,6-dichlorophenol (2,6-DCP) was accomplished by oxidation catalyzed by Coprinus cinereus peroxidase. Immobilization of the enzyme in a polyacrylamide matrix enhanced DCP oxidation. Hydrogen peroxide, peroxidase's natural substrate, was produced enzymatically in situ to avoid peroxidase inactivation by its too high concentration.

New highly selective inhibitors of class II fructose-1,6-bisphosphate aldolases.

Phosphoglycolo amidoxime and phosphoglycolo hydrazide, two new derivatives of phosphoglycolic acid, were synthesised and successfully tested as selective competitive inhibitors of class II FBP-aldolases.

A new strong inhibitor of beta-mannosidase.

N-phenyl-carbamate of D-mannonohydroxymolactone (I) was synthesized from mannose and was shown to be the best competitive inhibitor of beta-mannosidase so far reported (Ki = 25 nM).

Production of biosurfactants from sugar alcohols and vegetable oils catalyzed by lipases in a nonaqueous medium.

Porcine pancreatic and Chromobacterium viscosum lipases catalyze transesterification reactions between a number of sugar alcohols and various plant and animal oils in dry pyridine. The products of this process have been identified as primary monoesters of sugar alcohols and fatty acids. These enzymatically prepared sugar alcohol esters have been found to be excellent surfactants in terms of their ability to reduce interfacial and surface tensions and to stabilize emulsions.

[Biosynthesis of thiazole from thiamine in Escherichia coli].

The incorporation into the thiazole moiety of thiamine of several labeled compounds has been studied on short time incubations of washed-cells suspensions. No incorporation of radioactivity from [G-14C] methionine was found in a mutant auxotrophic for methionine. No radioactivity was incorporated from [U-14C] aspartate or from [U-14C] serine.