Enzyme-Triggered Chromogenic and Fluorogenic Probes for Myrosinase Activity Detection.

Myrosinase, a thioglucosidase, is a key enzyme in the mechanism of defense of plants that hydrolyzes glucosinolates (GSLs) into isothiocyanates. These isothiocyanates are the main bioactive molecules exerting protective effect in Brassicales plants. These plants that contain this specific enzyme-substrate couple belong to our daily human diet and have demonstrated health benefits, such as chemopreventive effects.

Artificial Fluorescent Glucosinolates (F-GSLs) Are Transported by the Glucosinolate Transporters GTR1/2/3.

The glucosinolate transporters 1/2/3 (GTR1/2/3) from the Nitrate and Peptide transporter Family (NPF) play an essential role in the transport, accumulation, and distribution of the specialized plant metabolite glucosinolates. Due to representing both antinutritional and health-promoting compounds, there is increasing interest in characterizing GTRs from various plant species. We generated seven artificial glucosinolates (either aliphatic or benzenic) bearing different fluorophores (Fluorescein, BODIPY, Rhodamine, Dansylamide, and NBD) and investigated the ability of GTR1/2/3 from to import the fluorescent glucosinolates (F-GSLs) into oocytes from .

Copper-catalyzed -arylation of Furanose-Fused Oxazolidine-2-thiones.

The 1,3-oxazolidine-2-thiones (OZTs) are important chiral molecules, especially in asymmetric synthesis. These compounds serve as important active units in biologically active compounds. Herein, carbohydrate anchored OZTs were explored to develop a copper-catalyzed C-S bond formation with aryl iodides.

The myrosinase-glucosinolate system to generate neoglycoproteins: A case study targeting mannose binding lectins.

A convenient strategy for a 'one-pot' synthesis of neoglycoproteins (NGP) was developed using the myrosinase-glucosinolate couple, a natural enzyme-substrate system. This enzymatic reaction allowed us to generate an isothiocyanate in situ which then reacted with the lysine residues of bovine serum albumin protein (BSA) to produce multivalent neoglycoproteins. Using two models, glucomoringin which is a natural glucosinolate bearing a l-rhamnose unit, and an artificial glucosinolate specifically designed for mannose type lectins, an average of up to 17.

Multigram scale preparation of a semi-synthetic N-trifluoroacetyl protected chondroitin disaccharide building block: Towards the stereoselective synthesis of chondroitin sulfates disaccharides.

The chemoselective N-trifluoroacetylation of a chondroitin disaccharide obtained from controlled acid hydrolysis of a commercially available polymeric chondroitin sulfate is reported for the first time. We also described the multi-gram scale synthesis of a donor block having a benzylidene moiety further used for the expeditious and stereocontrolled synthesis of glycosides fitted with various aglycons. Stereocontrolled β-glycosylation, sulfation and efficient N-TFA deprotection steps afforded the desired disaccharides in good yields.

Capillary electrophoresis with dual detection UV/CD for monitoring myrosinase-mediated hydrolysis of thiol glucosinolate designed for gold nanoparticle conjugation.

Capillary electrophoresis (CE) with dual UV and conductivity detection was used for the first time to monitor the functionalization of gold nanoparticles (AuNPs), a process catalyzed by an enzyme, myrosinase (Myr). A thiol glucosinolate (GL-SH) designed by our group was used as substrate. Hydrolysis of free and immobilized GL-SH was characterized using off-line and on-line CE-based enzymatic assays.

Diverted Natural Lossen-type Rearrangement for Bioconjugation through in Situ Myrosinase-Triggered Isothiocyanate Synthesis.

Fluorescein isothiocyanate (FITC) is one of the most extensively used fluorescent probes for the labeling of biomolecules. The isothiocyanate function reacts with lysine residues of proteins to provide a chemically stable thiourea linkage without releasing any byproduct. However, diversification of isothiocyanate-based reagents is still hampered by the lack of mild conditions to generate isothiocyanate chemical functions, as well as by their poor stability and limited solutions available to increase water solubility, restricting the use of isothiocyanate labeling to highly water-soluble fluorophores.

Glycerol carbonate in Ferrier reaction: Access to new enantiopure building blocks to develop glycoglycerolipid analogues.

Glycerol carbonate and tri-O-acetyl-D-glucal were used for the synthesis of glycero-functionalized carbohydrates. Ferrier reaction between the two partners afforded the O-glucoside in 84% yield. Spontaneous crystallization yielded 28% of a pure diastereoisomer with the S configuration as determined by X-ray crystallography.

UGT74B1 from Arabidopsis thaliana as a versatile biocatalyst for the synthesis of desulfoglycosinolates.

Thioglycosides, even if rare in Nature, have gained increased interest for their biological properties. Chemical syntheses of this class of compounds have been largely studied but little has been reported on their biosynthesis. Herein, combining experiments from the different fields of enzymology, bioorganic chemistry and molecular modeling, we wish to demonstrate the versatility of the glucosyltransferase UGT74B1 and its synthetic potency for the preparation of a variety of natural and unnatural desulfoglycosinolates.

Synthesis of 3-fluoropyrrolidines and 4-fluoropyrrolidin-2-ones from allylic fluorides.

Various 3-fluoropyrrolidines and 4-fluoropyrrolidin-2-ones were prepared by 5-exo-trig iodocyclisation from allylic fluorides bearing a pending nitrogen nucleophile. These bench-stable precursors were made accessible upon electrophilic fluorination of the corresponding allylsilanes. The presence of the allylic fluorine substituent induces syn-stereocontrol upon iodocyclisation with diastereomeric ratios ranging from 10:1 to > 20:1 for all N-tosyl-3-fluoropent-4-en-1-amines and amides.

New access to trisubstituted 3-pyrrolines under phosphine catalysis.

Conjugated dienes, properly activated by electron-withdrawing groups on both ends, are shown to be suitable substrates for phosphine-promoted organocatalytic processes. Their reactions with imines, under phosphine catalysis, afford a new and efficient synthetic approach to functionalized 3-pyrrolines.

Selective targeting of synthetic antioxidants to mitochondria: towards a mitochondrial medicine for neurodegenerative diseases?

Mitochondria are the major source of superoxide, and are responsible for activating apoptosis and oxidative damage during acute neuronal cell death and neurodegenerative disorders like Alzheimer and Parkinson diseases. While the molecular mechanisms by which mitochondrial oxidative stress triggers apoptosis are still investigated, attempts to achieve neuroprotection using antioxidant molecules have already been successful in several models of neuronal cell death. To increase the availability of antioxidant drugs at the mitochondrial level within cells, Michael P.