Search results for "HYDROLYSIS"
showing 10 items of 632 documents
The mechanism of formamide hydrolysis in water from ab initio calculations and simulations.
2005
The neutral hydrolysis of formamide in water is a suitable reference to quantify the efficiency of proteolytic enzymes. However, experimental data for this reaction has only very recently been obtained and the kinetic constant determined experimentally is significantly higher than that predicted by previous theoretical estimations. In this work, we have investigated in detail the possible mechanisms of this reaction. Several solvent models have been considered that represent a considerable improvement on those used in previous studies. Density functional and ab initio calculations have been carried out on a system which explicitly includes the first solvation shell of the formamide molecule…
Struktur-Wirkungs-Beziehungen bei Histaminanaloga, 13. Mitt.: 5(4)-Cyclisch substituierte Histamine und Nα-Methyl-histamine
1976
Es wird die Darstellung von 5(4)-cyclisch substituierten Histaminen und Nα-Methyl-histaminen durch Cyclisierung von 1-aryl-substituierten 2-Brom-4-phthalimido-butan-1-onen mit Formamid oder Benzamidin und anschliesende Hydrolyse bzw. Reduktion der Zwischenprodukte beschrieben. C-5(4) Cyclic Substituted Histamines and Nα-Methylhistamines The preparation of C-5(4) cyclic substituted histamines and Nα-methylhistamines by cyclisation of 1-aryl-2-bromo-4-phthalimidobutan-1-ones with formamide or benzamidine, followed by hydrolysis or reduction of the intermediates, is described.
Enzyme recovery and fouling mitigation by ultrasound-enhanced ultrafiltration
2013
Abstract The development of second-generation biofuels from cellulosic/lignocellulosic biomass has advantages from energy and environmental aspects, but the overall cost of the process is mainly dependent on the cost of the enzymes. Enzyme recovery and recycling is one of the most important and effective means of increasing the efficiency of enzymatic hydrolysis processes by lowering the enzyme costs. The primary objective of this study was to investigate the possibilities of enzyme recovery by membrane separation. Ultrafiltration (UF) membranes with various cut-off values and materials were used to recycle cellulase and cellobiase in model solutions and cellulosic hydrolysates. The membran…
Bioaccessibility and bioavailability of fumonisin B2 and its reaction products with isothiocyanates through a simulated gastrointestinal digestion sy…
2014
Abstract Fumonisins (FBs) are toxins produced mainly by the molds Fusarium verticillioides (also known as Fusarium moniliforme) and Fusarium proliferatum. These mycotoxins are contaminants of wheat, maize, maize-based foods and other grains worldwide. Isothiocyanates (ITCs) are natural compounds produced by the enzymatic hydrolysis of glucosinolates, which are found in plants of the Brassicaceae family. The use of ITCs as food preservatives has been extensively researched. In this study, allyl (AITC), phenyl (PITC) and benzyl isothiocyanates (BITC) fumigation systems (500 μL/L) were employed to reduce FB2 levels naturally produced in bread by Gibberella moniliformis CECT 2987. Reaction prod…
Ciclohexadespipeptide beauvericin degradation by different strains of Saccharomyces cerevisiae
2013
Abstract The interaction between the mycotoxin beauvericin (BEA) and 9 yeast strains of Saccharomyces cerevisiae named LO9, YE-2, YE5, YE-6, YE-4, A34, A17, A42 and A08 was studied. The biological degradations were carried out under aerobic conditions in the liquid medium of Potato Dextrose Broth (PDB) at 25 °C for 48 h and in a food/feed system composed of corn flour at 37 °C for 3 days, respectively. BEA present in fermented medium and corn flour was determined using liquid chromatography coupled to the mass spectrometry detector in tandem (LC–MS/MS) and the BEA degradation products produced during the fermentations were determined using the technique of the liquid chromatography coupled …
A new plant wide modelling approach for the reduction of greenhouse Gas emission from wastewater treatment plants
2017
Recent studies about greenhouse gas (GHG) emissions show that sewer collection systems and wastewater treatment plants (WWTPs) are anthropogenic GHG potential sources. Therefore, they contribute to the climate change and air pollution. This increasing interest towards climate change has led to the development of new tools for WWTP design and management. This paper presents the first results of a research project aiming at setting-up an innovative mathematical model platform for the design and management of WWTPs. More specifically, the study presents the project’s strategy aimed at setting-up a plant-wide mathematical model which can be used as a tool for reducing/controlling GHG from WWTP.…
Binding and/or hydrolysis of purine‐based nucleotides is not required for IM30 ring formation
2021
IM30, the inner membrane-associated protein of 30 kDa, is conserved in cyanobacteria and chloroplasts. Although its exact physiological function is still mysterious, IM30 is clearly essential for thylakoid membrane biogenesis and/or dynamics. Recently, a cryptic IM30 GTPase activity has been reported, albeit thus far no physiological function has been attributed to this. Yet, it is still possible that GTP binding/hydrolysis affects formation of the prototypical large homo-oligomeric IM30 ring and rod structures. Here, we show that the Synechocystis sp. PCC 6803 IM30 protein in fact is an NTPase that hydrolyzes GTP and ATP, but not CTP or UTP, with about identical rates. While IM30 forms lar…
Glycosylated macromolecular conjugates of antiviral drugs with a polyaspartamide.
2004
Two new polymeric conjugates for specific liver targeting were prepared by conjugation of sugar moieties and antiviral drugs to alpha, beta-poly[N-2-(hydroxyethyl)-DL-aspartamide] (PHEA). PHEA-galactopyranosylphenylthiocarbamide-mono-O-succinylganciclovir (conjugate 7) and PHEA-mannopyranosylphenylthiocarbamide-O-succinylacyclovir (conjugate 8) were synthesized according to a multi-step procedure which allowed for obtaining high product yield and process standardization. Conjugate 7 contained 7.5 and 8.5% of galactose and ganciclovir (substituent/repeating unit, mol/mol), respectively, and conjugate 8 contained 14.2 and 10.8% of mannose and acyclovir, respectively. In vitro studies demonstr…
Gelchromatographie, 12. Gelchromatographisches Verhalten von Polyvinylalkoholgelen
1975
Durch Hydrolyse von Copolymeren aus Vinylacetat und 1,4-Bis(vinyloxy)butan werden vernetzte Polyvinylalkoholgele hergestellt und ihre Eignung als hydrophile stationare Phase bei gelchromatographischen Trennungen mit Dextranen, Poly(athylenoxid)en und Proteinen als Testsubstanzen gepruft. Die Gele sind druck- und biostabil und zeigen keine storende Adsorption. Je nach Herstellungsbedingungen werden Ausschlusmolekulargewichte bis zu 106 erzielt. Hydrolysis of copolymers from vinyl acetate and 1,4-bis(vinyloxy)butane results in crosslinked poly(vinyl alcohol) gels. Their applicability as hydrophilic stationary phase in gel permeation chromatography is investigated using dextranes, poly(ethylen…
3H-1,2-benzoxathiepine 2,2-dioxides: a new class of isoform-selective carbonic anhydrase inhibitors
2017
Abstract A new chemotype with carbonic anhydrase (CA, EC 4.2.1.1) inhibitory action has been discovered, the homo-sulfocoumarins (3H-1,2-benzoxathiepine 2,2-dioxides) which have been designed considering the (sulfo)coumarins as lead molecules. An original synthetic strategy of a panel of such derivatives led to compounds with a unique inhibitory profile and very high selectivity for the inhibition of the tumour associated (CA IX/XII) over the cytosolic (CA I/II) isoforms. Although the CA inhibition mechanism with these new compounds is unknown for the moment, we hypothesize that it may be similar to that of the sulfocoumarins, i.e. hydrolysis to the corresponding sulfonic acids which therea…