From carbohydrate-derived ketene dithioacetals to 1--thioglycals: a synthetic and theoretical insight.

A strategy for the synthesis of 1--substituted thioglycals was developed from cyclic carbohydrate-derived ketene dithioacetals in a four-step sequence. The corresponding thioglycals, in two carbohydrate series, were first obtained by removal of the exocyclic glycosyl sulfoxide, followed by treatment with an organolithium reagent. Various electrophilic groups were introduced onto the thioglycal double bond after deprotonation and formation of a glycosyl lithium intermediate.

A novel bioactive and functional exopolysaccharide from the cyanobacterial strain Arthrospira maxima cultivated under salinity stress.

Cyanobacterial exopolysaccharides (EPS) remain released by cyanobacteria in the surrounding environment with the main purpose of protection against harmful environmental conditions. Recently, they have received significant attention due to their unique structural characteristics, functional properties, and potential applications across various fields. The current study describes the evaluation of EPS production under salinity stress from Arthrospira maxima.

An Integrated Enzymatic Approach to Produce Pentyl Xylosides and Glucose/Xylose Laurate Esters From Wheat Bran.

Alkyl glycosides and sugars esters are non-ionic surfactants of interest for various applications (cosmetics, food, detergency,…). In the present study, xylans and cellulose from wheat bran were enzymatically converted into pentyl xylosides and glucose and xylose laurate monoesters. Transglycosylation reaction catalyzed by the commercial enzymatic cocktail Cellic Ctec2 in the presence of pentanol led to the synthesis of pentyl β-D-xylosides from DP1 to 3 with an overall yield of 520 mg/g of xylans present in wheat bran.

d-Xylose and l-arabinose laurate esters: Enzymatic synthesis, characterization and physico-chemical properties.

Efficient enzymatic synthesis of d-xylose and l-arabinose lauryl mono- and diesters has been achieved by transesterification reactions catalysed by immobilized Candida antarctica lipase B as biocatalyst, in organic medium in the presence of d-xylose or l-arabinose and vinyllaurate at 50 °C. In case of l-arabinose, one monoester and one diester were obtained in a 57% overall yield. A more complex mixture was produced for d-xylose as two monoesters and two diesters were synthesized in a 74.

'Click'-xylosides as initiators of the biosynthesis of glycosaminoglycans: Comparison of mono-xylosides with xylobiosides.

Different mono-xylosides and their corresponding xylobiosides obtained by a chemo-enzymatic approach featuring various substituents attached to a triazole ring were probed as priming agents for glycosaminoglycan (GAG) biosynthesis in the xylosyltransferase-deficient pgsA-745 Chinese hamster ovary cell line. Xylosides containing a hydrophobic aglycone moiety were the most efficient priming agents. Mono-xylosides induced higher GAG biosynthesis in comparison with their corresponding xylobiosides.

Fluorophosphonylated nucleoside derivatives as new series of thymidine phosphorylase multisubstrate inhibitors.

The synthesis of new class of potential TPase inhibitors containing a difluoromethylphosphonate function as phosphate mimic is reported. This new series was prepared from a readily available fluorinated building block in few steps. Two series were evaluated as potential inhibitors: a linear series and a conformational constrained series.

Inactivation of S-adenosyl-L-homocysteine hydrolase by 6'-cyano-5',6'-didehydro-6'-deoxyhomoadenosine and 6'-chloro-6'-cyano-5',6'-didehydro-6'-deoxyhomoadenosine. Antiviral and cytotoxic effects.

6'-Cyano-5',6'-didehydro-6'-deoxyhomoadenosine (E)-1, (Z)-1, and 6'-chloro-6'-cyano-5',6'-didehydro-6'-deoxyhomoadenosine (E)-2 were synthesized and tested as new mechanism-based inhibitors of AdoHcy hydrolase. Nucleoside (E)-1 was identified as a type I inhibitor of the enzyme, whereas inactivation of the enzyme by nucleosides (Z)-1 and (E)-2 was accompanied by the formation of a covalent labeling of AdoHcy hydrolase.

Iminosugars as glycosyltransferase inhibitors: synthesis of polyhydroxypyrrolidines and their evaluation on chitin synthase activity.

Chitin synthase is an enzyme involved in the biosynthesis of chitin, a major structural component of the cell wall of many fungi. Since chitin is absent in vertebrates, chitin synthase has been envisaged as a valuable target in the search for new antifungal agents. In this report, a series of C-2 substituted polyhydroxypyrrolidines were designed and synthesized with the aim of mimicking the glycosylation involved at the transition state of the enzymatic reaction governed by chitin synthase.

Inactivation of human S-adenosylhomocysteine hydrolase by covalent labeling of cysteine 195 with thionucleoside derivatives.

A new series of 5'-thioadenosine derivatives 1-4 were synthesized for selectively targeting (195)Cys of human AdoHcy hydrolase. Their incubation with the enzyme resulted in time- and concentration-dependent inactivation, without major modifications of the NAD(+)/NADH ratio. The electrospray mass analysis of the inactivated enzyme with 1, 2, 3, and 4b showed that inhibition was accompanied by the formation of a specific and covalent labeling of each AdoHcy hydrolase subunit.

Inactivation of S-adenosylhomocysteine hydrolase with haloethyl and dihalocyclopropyl esters derived from homoadenosine-6'-carboxylic acid.

In a search for new inhibitors that exploit 5'-6' 'hydrolytic activity' of AdoHcy hydrolase, a new series of haloethyl and dihalocyclopropyl esters 2-3 were designed and their interaction with the enzyme studied. Incubation of the enzyme with 2-3 resulted in time- and concentration-dependent inactivation of AdoHcy hydrolase as well as almost total depletion of its NAD(+) content. Further results indicated that the 'oxidative' but not the 'hydrolytic' activity was involved in the inactivation process.