Search results for "Glycerol"
showing 10 items of 283 documents
Kinetic and functional characterization of a membrane-bound NAD(P)H dehydrogenase located in the chloroplasts of Pleurochloris meiringensis (Xanthoph…
1996
Using isolated chloroplasts or purified thylakoids from photoautotrophically grown cells of the chromophytic alga Pleurochloris meiringensis (Xanthophyceae) we were able to demonstrate a membrane bound NAD(P)H dehydrogenase activity. NAD(P)H oxidation was detectable with menadione, coenzyme Q0, decylplastoquinone and decylubiquinone as acceptors in an in vitro assay. K m-values for both pyridine nucleotides were in the μmolar range (K m[NADH]=9.8 μM, K m[NADPH]=3.2 μM calculated according to Lineweaver-Burk). NADH oxidation was optimal at pH 9 while pH dependence of NADPH oxidation showed a main peak at 9.8 and a smaller optimum at pH 7.5-8. NADH oxidation could be completely inhibited with…
Investigation of Polyol Adsorption on Ru, Pd, and Re Using vdW Density Functionals
2015
Biomass-based feedstocks are often oxygenated compounds characterized by large amounts of hydroxyls. As an example, polyols and sugar alcohols are largely employed as reactants for different chemical catalytic transformations such as oxidation, dehydration, and hydrodeoxigenation, which usually occur in aqueous medium. With the goal of gaining new insights into processes that could be industrially relevant, the adsorption of the OH groups on metal surfaces and in the presence of water has to be correctly reproduced and described, within a chosen theoretical framework. Toward this goal, several tests were performed on the catalytically relevant metal Ru, Pd, and Re, benchmarking their bulk a…
(1-Adamantyl)methyl glycidyl ether: a versatile building block for living polymerization.
2014
(1-Adamantyl)methyl glycidyl ether (AdaGE) is introduced as a versatile monomer for oxyanionic polymerization, enabling controlled incorporation of adamantyl moieties in aliphatic polyethers. Via copolymerization with ethoxyethyl glycidyl ether (EEGE) and subsequent cleavage of the acetal protection groups of EEGE, hydrophilic linear polyglycerols with an adjustable amount of pendant adamantyl moieties are obtained. The adamantyl unit permits control over thermal properties and solubility profile of these polymers (LCST). Additionally, AdaGE is utilized as a termination agent in carbanionic polymerization, affording adamantyl-terminated polymers. Using these structures as macroinitiators fo…
Binding of water-soluble, globular proteins to anionic model membranes
2009
Abstract The role of electrostatics is studied in the adsorption of proteins to negatively charged (phosphatidylcholine/phosphatidylglycerol, PC/PG) and neutral (PC) small unilamellar vesicles (SUVs). For model proteins the interaction is monitored vs . pH at low ionic strength. The adsorption behaviour of lysozyme, myoglobin and albumin (isoelectronic point, p I 5–11) is investigated in SUVs, along with changes of the fluorescence emission spectra of the charged proteins, via their adsorption on SUVs. Significant adsorption of the proteins to negatively charged SUVs is found only at pH values, where the number of positive charge moieties exceeds the number of negative charge moieties on th…
Ligand requirement for LHC I reconstitution
1998
Knowledge of the structure of photosynthetic light harvesting complexes is essential for understanding their function. Reconstitution of light harvesting complexes proved to be a very powerful tool for such structure analyses. In this way evidence was obtained for the central role of lutein and chlorophylls for LHCII structure (1) which was later confirmed by electron crystallographic analyses (2). Employing mutated, bacterial overexpressed LHCII apoproteins, amino acids could be identified which are involved in trimerization of LHCII and probably in binding of phosphatidylglycerol (3).
Polyunsaturated fatty acids in the modulation of T-cell signalling
2009
n-3 polyunsaturated fatty acids (PUFA) have been shown to modulate immune responses. These agents, being considered as adjuvant immunosuppressants, have been used in the treatment of various inflammatory and autoimmune diseases. However, the molecular mechanisms of action of n-3 PUFA-induced immunosuppressive effects are not well-understood. Since exogenous n-3 PUFA, under in vitro and in vivo conditions, are efficiently incorporated into T-cell plasma membranes, a number of recent studies have demonstrated that these agents may modulate T-cell signalling. In this review, the interactions of n-3 PUFA with the second messenger cascade initiated during early and late events of T-cell activati…
Mesogen-Initiated Linear Polyglycerol Isomers: The Ordering Effect of a Single Cholesterol Unit on “Sticky” Isotropic Chains
2011
Synthesis, thermal properties, and the liquid crystalline (LC) order of polymers consisting of a single mesogenic cholesterol unit and flexible, linear polyglycerol (PG) or poly(glyceryl glycerol) (PGG) chains have been investigated. Incorporation of the single mesogen has been achieved by using cholesterol directly as an initiator for the oxyanionic ring-opening polymerization (ROP) of ethoxyethyl glycidyl ether (EEGE) or isopropylidene glyceryl glycidyl ether (IGG). The controlled polymerization allowed the synthesis of a series of peculiar rod–coil type polyethers with molecular weights of 600–2300 g/mol, representing a degree of polymerization (DPn) of 4–30 for both PG and PGG with the …
Poly(1,2-glycerol carbonate): A Fundamental Polymer Structure Synthesized from CO2 and Glycidyl Ethers
2013
The functional, aliphatic poly(1,2-glycerol carbonate) as a fundamental, simple polymer structure based on glycerol and CO2 was prepared by combination of glycidyl ether monomers with carbon dioxide via two different approaches. The material was obtained by two-step procedures either via copolymerization of (i) ethoxy ethyl glycidyl ether (EEGE) or (ii) benzyl glycidyl ether (BGE) with CO2, followed by removal of the respective protecting groups via acidic cleavage for (i) and hydrogenation for (ii). The resulting protected polycarbonate structures and the targeted poly(1,2-glycerol carbonate) were investigated with 1H NMR and 13C NMR spectroscopy as well as 2D-NMR methods. Removal of both …
Regulatory activity of polyunsaturated fatty acids in T-cell signaling.
2009
n-3 Polyunsaturated fatty acids (PUFA) are considered to be authentic immunosuppressors and appear to exert beneficial effects with respect to certain immune-mediated diseases. In addition to promoting T-helper 1 (Th1) cell to T-helper 2 (Th2) cell effector T-cell differentiation, n-3 PUFA may also exert anti-inflammatory actions by inducing apoptosis in Th1 cells. With respect to mechanisms of action, effects range from the modulation of membrane receptors to gene transcription via perturbation of a number of second messenger cascades. In this review, the putative targets of anti-inflammatory n-3 PUFA, activated during early and late events of T-cell activation will be discussed. Studies h…
Evidence for the involvement of acylglycerides on chitin synthetase activity inCandida albicans
1991
The effect of a lipase activity (EC 3.1.1.3) on the chitin synthetase from Candida albicans has been studied, both on the active and the trypsin activated enzyme. Removal of fatty acids from acylglycerides by lipase has an inhibitory effect on the activity as well as on the ‘in vitro’ activation process by trypsin in the membrane-bound enzyme and in the chitosomes. This would indicate that an adequate lipid environment is required for both the activation process and proper function of the synthetase activity.