251340-45-1Relevant academic research and scientific papers
Redesign of the Active Site of Sucrose Phosphorylase through a Clash-Induced Cascade of Loop Shifts
Kraus, Michael,Grimm, Clemens,Seibel, Jürgen
, p. 33 - 36 (2016/01/15)
Sucrose phosphorylases have been applied in the enzymatic production of glycosylated compounds for decades. However, several desirable acceptors, such as flavonoids or stilbenoids, that exhibit diverse antimicrobial, anticarcinogenic or antioxidant properties, remain poor substrates. The Q345F exchange in sucrose phosphorylase from Bifidobacterium adolescentis allows efficient glucosylation of resveratrol, (+)-catechin and (-)-epicatechin in yields of up to 97 % whereas the wild-type enzyme favours sucrose hydrolysis. Three previously undescribed products are made available. The crystal structure of the variant reveals a widened access channel with a hydrophobic aromatic surface that is likely to contribute to the improved activity towards aromatic acceptors. The generation of this channel can be explained in terms of a cascade of structural changes arising from the Q345F exchange. The observed mechanisms are likely to be relevant for the design of other tailor-made enzymes.
Enzymatic Glycosylation of Phenolic Antioxidants: Phosphorylase-Mediated Synthesis and Characterization
De Winter, Karel,Dewitte, Griet,Dirks-Hofmeister, Mareike E.,De Laet, Sylvie,Pelantová, Helena,K?en, Vladimír,Desmet, Tom
, p. 10131 - 10139 (2016/02/03)
Although numerous biologically active molecules exist as glycosides in nature, information on the activity, stability, and solubility of glycosylated antioxidants is rather limited to date. In this work, a wide variety of antioxidants were glycosylated using different phosphorylase enzymes. The resulting antioxidant library, containing α/β-glucosides, different regioisomers, cellobiosides, and cellotriosides, was then characterized. Glycosylation was found to significantly increase the solubility and stability of all evaluated compounds. Despite decreased radical-scavenging abilities, most glycosides were identified to be potent antioxidants, outperforming the commonly used 2,6-bis(1,1-dimethylethyl)-4-methylphenol (BHT). Moreover, the point of attachment, the anomeric configuration, and the glycosidic chain length were found to influence the properties of these phenolic glycosides.
Synthesis of epicatechin glucosides by a β-cyclodextrin glycosyltransferase
Aramsangtienchai, Pornpun,Chavasiri, Warinthorn,Ito, Kazuo,Pongsawasdi, Piamsook
experimental part, p. 27 - 34 (2012/02/06)
Enzymatic synthesis of (-)-epicatechin (EC) glucosides was performed through the transglucosylation reaction catalyzed by the cyclodextrin glycosyltransferase (CGTase) from Paenibacillus sp. RB01. The enzyme showed the same product specificity for the three donor substrates, starch, β-cyclodextrin and maltoheptaose (G7). Using β-cyclodextrin as the glucosyl donor, several EC glucoside products were obtained at an overall minimal yield of 18.1%. The structures of the four main products were elucidated by MS and NMR techniques as (-)-EC-3′-O-α-d-glucopyranoside (EC3A), (-)-EC-3′-O-α-d-diglucopyranoside (EC3B), (-)-EC-3′-O- α-d-triglucopyranoside (EC3C) and (-)-EC-4′-O-α-d- glucopyranoside (EC4A). Of these, EC3A was the major product while EC4A, unique for this CGTase, was formed in the lowest amount. The water solubility and stability against UV irradiation of EC3A were significantly higher than that of EC. Although the antioxidant activity was 1.5-fold lower, the advantage of the enhanced solubility and stability makes the EC3A glucoside more beneficial as food ingredient than its parent EC.
