The enzymes from the alpha-amylase family all share a similar alpha-retaining catalytic mechanism but can have different reaction and product specificities. One family member, cyclodextrin glycosyltransferase (CGTase), has an uncommonly high transglycosylation activity and is able to form cyclodextrins. We have determined the 2.0 and 2.5 A X-ray structures of E257A/D229A CGTase in complex with ...

In this study, attempts were made to investigate the effects of beta-cyclodextrin (beta-CD) on the aqueous solubility and dissolution rate of celecoxib. Inclusion complexes were prepared by the kneading method and characterized by SEM, NMR, IR, DSC, and X-ray powder diffraction. Dissolution rate of the complexes was significantly greater than that of the corresponding physical mixtures and pure...

The aim of this study was to characterize new nanoparticles (NPs) containing chitosan (CS), or CS/cyclodextrin (CDs), and evaluate their potential for the oral delivery of the peptide glutathione (GSH). More precisely, NP formulations composed of CS, CS/alpha-CD and CS/sulphobutyl ether-beta-cyclodextrin (SBE(7m)-beta-CD) were investigated for this application. CS/CD NPs showed particle sizes r...

Lipid rafts and caveolae are specialized membrane microdomains implicated in regulating G protein-coupled receptor signaling cascades. Previous studies have suggested that rafts/caveolae may regulate beta-adrenergic receptor/Galpha(s) signaling, but underlying molecular mechanisms are largely undefined. Using a simplified model system in C6 glioma cells, this study disrupts rafts/caveolae using...

Structure-prediction and hydrophobic-cluster analysis of several starch hydrolases and related enzymes indicated the organization of eleven domain types. Most enzymes possess a catalytic (beta/alpha)8-barrel and a smaller C-terminal domain as seen in crystal structures of alpha-amylase and cyclodextrin glucanotransferase. Some also have a starch-granule-binding domain. Enzymes breaking or formi...

Low concentrations of cyclodextrins (< 1.0 mM) added to serum act catalytically, accelerating the exchange of cholesterol between cells and lipoproteins. J774 macrophages incubated with serum and 2-hydroxypropyl-beta-cyclodextrin (< or = 1 mM) released fivefold more labeled cholesterol than with serum alone. Increased efflux was not accompanied by a change in cell cholesterol mass; thus, cyclod...

We have prepared a novel kind of building block (CD-PI-CD) of polyether imide (PI) with beta-cyclodextrin (beta-CD) at the both ends that self-assembles into vesicles in water. The vesicles are "reactive" in supramolecular chemistry because the host groups of beta-CD equally distribute on the inside and outside surfaces of the vesicles. Isothermal titration calorimetry (ITC) and static light sc...

To perform chiral separation of three flavonoid racemates, including dihydrodaidzein, equol and alpinetin, a simple and effective method was developed by using sulfobutyl ether-beta-cyclodextrin (SBE-beta-CD) as a mobile phase additive in HPLC system. The effects of different factors on the chiral separation were investigated, including cyclodextrin (CD) types (alpha-CD, gamma-CD, beta-CD, meth...

An X-ray structure analysis of a crystal of mutant Asp229----Ala of cyclodextrin glycosyltransferase from Bacillus circulans (Ec 2.4.1.19) that had been shortly exposed to beta-cyclodextrin showed density corresponding to a maltose bound at the catalytic center. The crystal structure was refined to an R-factor of 18.7% at 2.5-A resolution. The catalytic center is defined by homology with the st...

In the present study, an attempt was made to develop a cyclodextrin-colchicine complex and to study its effect on skin permeation and deposition of colchicine. Colchicine beta cyclodextrin (BCD) complex was prepared by freeze-drying method and complex formation was confirmed by NMR and in vitro drug release study. Formulation containing cyclodextrin-drug complex showed 6-fold increase in transd...