Microgel-Catalyzed Hydrolysis of Nonactivated Disaccharides

Abstract

The controlled and selective hydrolysis of underivatized disaccharides and oligosaccharides remains a challenge that is met by enzymatic and nonenzymatic approaches. In an effort to capitalize on recent progress in the development of functional enzyme mimics for the hydrolysis of glycosidic bonds, we developed cross-linked microgels with embedded binuclear copper­(II) complexes that are shown here to hydrolyze 1→4 over 1→6 glycosidic bonds under mildly alkaline conditions at elevated temperatures. The microgel catalysts show an unusual preference for the hydrolysis of 1→4β- over 1→4α-glycosidic bonds yielding up to 25 μg L–1 of glucose from cellobiose over 72 h and about half of that during the hydrolysis of maltose after correction for background effects. The experimental results are supported by computational analyses of the interactions between the embedded catalyst and the nonactivated disaccharide in putative transition state structures of the assembly during hydrolysis of the nonactivated glycosidic bond to rationalize this observation.

Synergistic Hydrolysis of Cellulose by a Blend of Cellulase-Mimicking Polymeric Nanoparticle Catalysts

“…Scheme shows our method to create an endocellulase mimic via covalent molecular imprinting and postmodification of the imprinted sites. Molecular imprinting is a powerful technique to create tailor-made binding sites in a cross-linked polymer network using template molecules (T) as space holders and polymerizable functional monomers (FMs) to bind the templates. − Molecularly imprinted materials have found wide applications, − including in catalysis. − In our case, the imprinting was performed in cross-linked surfactant micelles to afford polymeric NPs similar to proteins in size and water solubility.…”

Nanogel Catalysts for the Hydrolysis of Underivatized Disaccharides Identified by a Fast Screening Assay

“…Our previously developed 10 mL scale synthesis for polyacrylate gels coupled with subsequent purification by dialysis is based on the same strategy. , The approach provides catalysts with the ability to selectively hydrolyze glycosidic bonds in alkaline solution and near-neutral pH values. − Along these lines, a myriad of interactions were probed for their contributions to the formation and stabilization of the transition states of glycolysis including H-bonding interactions with the immobilized metal complex and the surrounding matrix. − Very recently, polyacrylate gels were also developed as catalysts for the hydrolysis of underivatized di- and oligosaccharides . However, their analysis added an additional step to the characterization and evaluation of the targeted hydrolysis function, as underivatized saccharides do not possess a chromophore and, therefore, do not facilitate a spectroscopic evaluation of the reaction.…”

Dynamic Tuning in Synthetic Glycosidase for Selective Hydrolysis of Alkyl and Aryl Glycosides

“…Interestingly, mobility of the aglycon of the substrate in the active site was found critical to the catalyzed hydrolysis and the “most fitted” active site had the lowest catalytic activity. Selective hydrolysis of glycosides is highly challenging and only a few examples have been reported to hydrolyze activated aryl glycosides. − Alkyl glycosides are far more stable than the commonly used p -nitrophenyl glycosides and thus much more difficult to hydrolyze . The half-life of methyl β- d -glucopyranoside, for example, is about 4.7 million years at 25 °C over pH 7–14 .…”

“…23−27 far more stable than the commonly used p-nitrophenyl glycosides and thus much more difficult to hydrolyze. 28 The half-life of methyl β-D-glucopyranoside, for example, is about 4.7 million years at 25 °C over pH 7−14. 29 Meanwhile, they represent an important class of biomoleculesthat is, glycolipidsand play vital roles in biological processes such as cell growth, cell trafficking, and cancer development.…”