alpha-cyclodextrin and tyloxapol

Supermolecular hydrogels were prepared by α-cyclodeatrin (α-CD) and Tyloxapol, which can be considered as an oligomer of the nonionic surfactant polyoxyethylene tert-octylphenyl ether (TX-100) with a polymerization degree below 7. Two carbon materials, graphene oxide (GO) and graphene, were mixed into the α-CD/Tyloxapol hydrogel to adjust the physicochemical properties of hydrogel. In order to get stable graphene dispersion and then mix it with α-CD/Tyloxapol hydrogel, both TX-100 and Tyloxapol were used to disperse graphene for comparison. Interestingly, it can be found that TX-100 could disperse graphene better than Tyloxapol owing to smaller molecular size of TX-100 compared with Tyloxapol. Then, both the α-CD/Tyloxapol/GO and α-CD/Tyloxapol/graphene hydrogels were characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, small angle X-ray scattering (SAXS), X-ray diffraction (XRD) and rheological measurements. The results revealed that the addition of carbon materials into α-CD/Tyloxapol hydrogel can change their microstructures and the rheological properties. Furthermore, it can be confirmed that a little amount of carbon materials could induce fluorescence quenching sharply which could be a promising candidate for optical sensor.

Topics: alpha-Cyclodextrins; Carbon; Hydrogels; Macromolecular Substances; Nanostructures; Particle Size; Polyethylene Glycols; Surface Properties

Lignoceroyl-CoA ligase activity has been detected in microsomal fractions prepared from rat brain. The synthesis of lignoceroyl-CoA from [1-14C]lignoceric acid and CoASH by this enzyme had an absolute dependence on ATP and Mg2+; ATP could not be replaced by GTP [I. Singh, M. S. Kang, and L. Phillips (1982) Fed. Proc. 41, 1192]. The product has been characterized as lignoceroyl-CoA by the following criteria: Rf on thin-layer chromatography; incorporation of [1-14C]lignoceric acid and [3H]CoASH into the product; acid hydrolysis and identification of the radiolabel in lignoceric acid; and methanolysis and identification of the radiolabel in methyl lignocerate by thin-layer chromatography. The optimal concentrations for CoASH, ATP, and Mg2+ were about 100 microM, 10 mM, and 5 mM, respectively. Lignoceric acid, solubilized by alpha-cyclodextrin, Triton X-100, and deoxycholate, was utilized by the lignoceroyl-CoA ligase, but lignoceric acid solubilized by Triton WR-1339 was not. Topographical localization of lignoceroyl-CoA ligase in the plane of rat brain microsomal membranes was determined by the use of Triton X-100, trypsin, and mercury-Dextran, and was compared with the marker enzymes, ethanol acyltransferase and thiamine pyrophosphatase, which are known to be localized on the luminal (inner) surface of the microsomal vesicles. Mercury-Dextran (100 microM) and trypsin (trypsin:microsomes, 1:56 w/w) treatment of the microsomes inhibited the lignoceroyl-CoA ligase activity by 70 and 90% without disrupting the microsomal vesicles. Disruption of the vesicles with Triton X-100 increased the activity of both ethanol acyltransferase and thiamine pyrophosphatase by 400% but there was no increase in lignoceroyl-CoA ligase activity. These results suggest that lignoceroyl-CoA ligase is localized on the cytoplasmic surface of the microsomal vesicles.

Topics: Adenosine Triphosphate; alpha-Cyclodextrins; Animals; Brain; Coenzyme A; Coenzyme A Ligases; Cyclodextrins; Detergents; Dextrans; Female; Magnesium; Male; Mercury; Microsomes; Octoxynol; Organomercury Compounds; Polyethylene Glycols; Rats; Rats, Inbred Strains; Thiamine Pyrophosphatase; Trypsin