Centro de Química Estrutural, Complexo 1, Instituto Superior Técnico, Lisboa, Portugal.
Published: February 2004
AI Article Synopsis
Article Abstract
The effect of beta-lactoglobulin encapsulation in sodium bis(2-ethylhexyl) sulfosuccinate reverse micelles on the environment of protein and on Trp was analysed at different water contents (omega0). CD data underlined the distortion of the beta-sheet and a less constrained tertiary structure as the omega0 increased, in agreement with a concomitant red shift and a decrease in the signal intensity obtained in steady-state fluorescence measurements. Fluorescence lifetimes, evaluated by biexponential analysis, were tau1 = 1.28 ns and tau2 = 3.36 ns in neutral water. In reverse micelles, decay-associated spectra indicated the occurrence of important environmental changes associated with omega0. Bimolecular fluorescence quenching by CCl4 and acrylamide was employed to analyse alterations in the accessibility of the two Trp residues in beta-lactoglobulin, induced by changes in omega0. The average bimolecular quenching constant was found not to depend on omega0, confirming the insolubility of this quencher in the aqueous interface, while increases with omega0. The drastic decrease with omega0 of kq, associated with the longest lifetime kq2(CCl4), comparatively to the increase of kq2(acrylamide), emphasizes the location of beta-lactoglobulin in the aqueous interfacial region especially at omega0> or = 10. The fact that (omega0 = 30) >> kq2(acrylamide) (water) also confirms the important conformational changes of encapsulated beta-lactoglobulin.
Pyrene fluorescence in aqueous solutions of two surface active ionic liquids, namely, 1-decyl-3-methylimidazolium chloride, and 1-hexadecyl-3-methylimidazolium chloride was investigated in presence of a biopolymer sodium alginate. The principal objective of this study was to explore the influence of the length of the hydrocarbon tails of these surface active ionic liquids on the possible location of the probe (pyrene) molecules in presence of the additive. While an abrupt decrease in the values of the ratio of the intensity of the first vibronic band to that of the third band of pyrene emission spectrum with concentration was observed for 1-hexadecyl-3-methylimidazolium chloride in presence of sodium alginate like the polymer-free case reported earlier, there was a peculiar reversal for 1-decyl-3-methylimidazolium chloride + sodium alginate.
The objective of this study was to investigate the antioxidant mechanism of action of fucoidan in sunflower oil and its oil-in-water emulsion. In addition, the effect of lecithin on the antioxidant mechanism of action of fucoidan in sunflower oil was investigated. In sunflower oil, fucoidan at 0.
A medium containing reverse micelles supports non-hydrogenative parahydrogen induced polarization (nhPHIP) in the organic phase while solubilizing a protein in the aqueous phase. Strongly enhanced NMR signals from iridium hydride complexes report on a ligand, 4-amino-2-benzylaminopyrimidine, which crosses the phase boundary and interacts with the thiaminase protein TenA. The calculation of binding equilibria reveals a of 39.
Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569, United States.
While glucose-responsive insulin delivery systems are in widespread clinical use to treat insulin insufficiency, the on-demand supplementation of glucagon for acute hypoglycemia treatment remains understudied. A self-regulated glucagon release material is highly desired to mitigate the potential risks of severe insulin-induced hypoglycemia. Here, we describe a glucose-responsive polymeric nanosystem with glucagon covalently grafted to the end-group.
Postpolymerization modifications are valuable techniques for creating functional polymers that are challenging to synthesize directly. This study presents aliphatic polycarbonates with pendant thiol-reactive groups for disulfide formation with mercaptans. The reductive responsive nature of this reaction allows for reversible postpolymerization modifications on biodegradable scaffolds.
