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All total 17 Articles be foundSynthesis and supramolecular properties of regioisomers of mononaphthylallyl derivatives of v-cyclodextrin
Bláhová, Markéta,Filippov, Sergey K.,Ková?ik, Lubomír,Horsky, Ji?í,Hybelbauerová, Simona,Syrová, Zdenka,K?í?ek, Tomá?,Jind?ich, Jind?ich
, p. 2509 - 2520 (2017)
Monosubstituted derivatives of γ-cyclodextrin (γ-CD) are suitable building blocks for supramolecular polymers, and can also serve as precursors for the synthesis of other regioselectively monosubstituted γ-CD derivatives. We prepared a set of monosubstituted 2I-O-, 3I-O-, and 6I-O-(3-(naphthalen-2-yl)prop-2-en-1-yl) derivatives of γ-CD using two different methods. A key step of the first synthetic procedure is a cross-metathesis between previously described regioisomers of mono-O-allyl derivatives of γ-CD and 2-vinylnaphthalene which gives yields of about 16-25% (2-5% starting from γ-CD). To increase the overall yields, we have developed another method, based on a direct alkylation of γ-CD with 3-(naphthalen-2-yl)allyl chloride as the alkylating reagent. Highly regioselective reaction conditions, which differ for each regioisomer in a used base, gave the monosubstituted isomers in yields between 12-19%. Supramolecular properties of these derivatives were studied by DLS, ITC, NMR, and Cryo-TEM.
A novel cyclodextrin glucanotransferase from alkaliphilic Bacillus pseudalcaliphilus 20RF: Purification and properties
Atanasova, Nikolina,Kitayska, Tsvetina,Bojadjieva, Ivanka,Yankov, Dragomir,Tonkova, Alexandra
, p. 116 - 122 (2011)
A new cyclodextrin glucanotransferase (CGTase, EC 2.4.1.19) from the obligated alkaliphile Bacillus pseudalcaliphilus 20RF, isolated from Bulgarian soils, was purified up to 18-fold by ultrafiltration and starch adsorption with a recovery of 63% activity. The enzyme was a monomer with a molecular weight 70 kDa estimated by SDS-PAGE. The CGTase exhibited two pH optima at pH 6.0 and 9.0 and was optimally active at 60 °C. The enzyme could be effectively used for conversion of raw starch into cyclodextrins (CDs) in a wide pH range, from 5.0 to 10.0 and temperatures 60-70 °C. The enzyme was more heat resistant after its pretreatment in alkaline pH 9.0 at high temperatures 65-70 °C, than at pH 6.0 under the same reaction conditions. The CGTase showed a significant stability in the presence of 15 mM various metal ions and reagents after 30 min incubation at 25 °C. The purified CGTase could be used for an efficient cyclodextrin production without any additives which is of an industrial interest. The achieved high conversion of an insoluble raw commercial corn starch into cyclodextrins (47%) with production of only two types of cyclodextrins, β- and γ-CD (80%:20%) in alkaline pH 9.0, makes B. pseudalcaliphilus 20RF CGTase industrially desired for cyclodextrin manufacture.
Altered product specificity of a cyclodextrin glycosyltransferase by molecular imprinting with cyclomaltododecaose
Kaulpiboon, Jarunee,Pongsawasdi, Piamsook,Zimmermann, Wolfgang
experimental part, p. 480 - 485 (2011/12/02)
Cyclodextrin glycosyltransferases (CGTases), members of glycoside hydrolase family 13, catalyze the conversion of amylose to cyclodextrins (CDs), circular α-(1,4)-linked glucopyranose oligosaccharides of different ring sizes. The CD containing 12 α-D-gluc
