Search results for "Glycerol"

Enzyme-mediated enantioselective acylation of secondary amines in organic solvents

1991

Abstract Porcine pancreatic lipase (PPL) and lipase Amano P catalyze the enantioselective acylation of cyclic 1,2- and 1,3-amino alcohol derivatives in organic solvents. The enatiomeric excesses (ee′s) were shown to depend on the enzyme, reaction time, temperature and type of substrate.

Study of a lipase from Candida rugosa Diddens and Lodder

1993

Lipasic system of Candida rugosa (CBS 613) strain was studied. The enzyme was purified in one step by hydrophobic chromatography. The properties of this lipase were determined. It is an oligomeric enzyme composed of five identical monomers of 46 kg · mol−1. Its optimum reaction conditions are pH = 7 and temperature = 40°C. This enzyme presents a rapid thermal denaturation and then a more stable form. It is a cell-bound lipase which is induced by triacyl glycerols. This enzyme presents a high specificity for external positions on glycerol. Unterschung einer Lipase aus Candida rugosa Diddens und Lodder Die Reinigung einer Lipase aus Candida rugosa (CBS 613) wurde in einer einzigen Stufe durch…

Lipase-enhanced activity in flavour ester reactions by trapping enzyme conformers in the presence of interfaces

1998

In order to improve the lipase-catalyzed synthesis of flavour esters, we have used the reported strategy of interfacial activation-based molecular (bio)imprinting [Mingarro et al. 1995. Proc. Natl. Acad. Sci. U.S.A. 92: 3308], later called trapping in the presence of amphiphile interfaces (TPI) [Mingarro et al. 1996. Biochemistry 35: 9935]. Five lipases of fungal and mammalian origin typically used for esterification process have been explored to improve production by TPI treatment. A marked enhancement of enzymatic activity has been observed in all TPI-treated lipases assayed and the activation factor obtained was up to 90-fold. The dependence on chain length of acyl donors in the esterifi…

Polymer ester von sären des phosphors, 7. Polymerisation des 1-oxo-2,6,7-trioxa-1-phosphabicyclo[2.2.1]heptans

1981

1-Oxo-2,6,7-trioxa-1-phosphabicyclo[2.2.1]heptane is transformed in situ (prepared from trimethyl phosphite and glycerol) at −78°C in the presence of a trace of water into a crosslinked polymer containing constitutional repeating units with 5- and 6-membered rings. The reaction with reagents containing hydroxyl groups (water, acetic acid, alcohol) leads to the degradation of the network with the formation of soluble fragments with Pn = 35–50. This reactivity and the possibility to obtain other derivatives from the fragments make this polymer a carrier for pharmacologically active polymers with the advantage of decomposing only into the innocuous components phosphoric acid and glycerol.

Der Verteilungsraum von physikalisch gelöstem Sauerstoff in wäßrigen Lösungen organischer Substanzen / The Distribution Space of Physically Dissolved…

1976

Abstract In order to evaluate the distribution of molecular oxygen in biological systems, the oxygen solubility (ml/ml atm) at 37 °C in aqueous solutions of thirty organic substances with different concentrations was measured by the classical Van Slyke principle. The oxygen solubility always (with the exception of hemoglobin) decreases exponentially with increasing concentration of the respective substance. In all cases this behavior is described highly significant by a simple empiric exponential function, when the substance concentration as well as the oxygen solubility of pure water is given. The influence of one substance on oxygen solubility contributes additively to the over-all solubi…

Influence of a hydrophilic spacer on the structure of a phospholipid monolayer

1994

We present the results of thermodynamical and X-ray grazing incidence diffraction experiments performed on Langmuir monolayers of ether lipids with hydrophilic spacers between the glycerol backbone and the phosphatidylcholine head group: DHPC, DH-E01-PC, and DH-E02-PC. As a spacer the oxy-ethylene group is used, which is a typical hydrophilic unit of non-ionic tensides. It turns out that the introduction of the hydrophilic spacers leads to a fluidization of the monolayer and reduces the tilt angle of the chains.

Corrigendum to “Phase equilibria for the ternary systems ethanol, water + ethylene glycol or + glycerol at 101.3 kPa” [Fluid Phase Equilib. 341 (2013…

2013

Synthesis of hyacinth, vanilla, and blossom orange fragrances: the benefit of using zeolites and delaminated zeolites as catalysts

2004

The synthesis of phenylacetaldehyde glycerol acetals, 2-benzyl-4-hydroxymethyl-1,3-dioxolane (1), 2-benzyl-5-hydroxy-1,3-dioxane (2), and vanillin propylene glycol acetal (2-(4-hydroxy-3-methoxyphenyl)-4-methyl-1,3-dioxolane) (3) which are flavoring compounds with hyacinth and vanilla scent fragrances, have been carried out successfully by acetalization of phenylacetaldehyde and vanillin with glycerol and propylene glycol, respectively, using toluene as solvent and zeolite catalysts whose adsorption properties have been optimized. However, in the case of a larger size acetal such as 2-acetonaphthone propylene glycol acetal (4) with blossom orange scent, geometrical constraints make the diff…

P4140Myeloid but not endothelial expression of the CB2 receptor promotes atherogenesis in the context of elevated levels of the endocannabinoid 2-ara…

2019

Abstract Background The endocannabinoid 2-arachidonoylglycerol (2-AG) is an inflammatory mediator and ligand to the cannabinoid receptors CB1 and CB2, which are expressed on myeloid and endothelial cells. 2-AG has recently been described to promote atherogenesis in ApoE-deficient mice. While the CB2 receptor has previously been considered to solely exert anti-inflammatory and atheroprotective effects, newer data have raised the notion, that CB2 might exert atherogenic effects in the context of elevated 2-AG plasma levels. In the present study, we investigated the atherogenic mechanisms of 2-AG and the role of the CB2 receptor on myeloid and endothelial cells in atherogenesis using cell-spec…

Auswirkungen parenteraler Glycerinzufuhr auf die Glycerokinase-Aktivität und den Adenosintriphosphatspiegel in der Niere von Ratten

1975

Dauerinfusionen mit Glycerin an Ratten fuhren bei Dosierungen oberhalb der durchschnittlichen maximalen Umsatzkapazitat (0,74 g.kg−1.h−1) zu Veranderungen an den Nieren in Form einer Gewichtszunahme bei gleichzeitiger Proteinverarmung und eines Aktivitatsverlustes an Glycerokinase bei deren gleichzeitigem Auftreten im Harn. Bei Dosierungen von 0,6 g.kg−1.h−1 und mehr kommt es zu einem ATP-Abfall in den Nieren. Im Gegensatz dazu sind Veranderungen in der Leber uneinheitlicb und in ahnlicher Form nur bei Dosierungsraten oberhalb der maximalen Umsatzkapazitat zu finden. Die auftretenden Veranderungen werden im Zusammenhang biokinetischer Daten und des Begriffs der osmotischen Nephrose diskutie…