Acetone

About: Acetone is a research topic. Over the lifetime, 9458 publications have been published within this topic receiving 120867 citations. The topic is also known as: propanone & dimethylketone.

Stabilization of Enzyme Activity by an Organic Solvent

Abstract: BIOCHEMICAL work with unstable enzymes is often handicapped by the loss of their enzyme activity during preparation and storage, and the instability of the enzymes makes their further purification and study difficult. A number of enzymes can be stabilized with the use of reducing agents, chelating compounds, competitive inhibitors, co-enzymes, and substrates and their analogues. Recently, Nozaki, Kagamiyama and Hayaishi1 have found that metapyrocatechase from Pseudomonas sp., which is very unstable, particularly in the presence of air, is stabilized by the presence of a low concentration of an organic solvent such as acetone or ethanol, and this observation led to its purification and crystallization. This has led us to investigate whether organic solvents have a stabilizing effect on a wide variety of enzymes. In this communication we report the effects of acetone and ethanol in stabilizing benzylalcohol dehydrogenase from Pseudomonas sp., homogentisicase from bovine liver, and alcohol dehydrogenase from yeast.

Effects of various alkali–acid additives on the activity of a manganese oxide in the catalytic combustion of ketones

Abstract: The catalytic combustion of acetone and methyl-ethyl-ketone (MEK) has been studied over a manganese oxide, Mn 2 O 3 . The reactant conversion has been followed as a function of the reaction temperature and it has been observed that lower temperatures are required for the combustion of acetone than for MEK. The performance of Mn 2 O 3 in the combustion reactions when alkali and acid ions are added to the oxide has also been investigated. A significant improvement of the catalyst performance is observed when Cs + and Na + are used as additives. The data of the ignition curves have been fitted to a simplified model where both ketone combustion reactions are assumed to have power law rate equations, which are first-order with respect to the corresponding organic molecule and do not depend on the oxygen partial pressure. Differences in the apparent activation energy values estimated with this model for acetone and MEK combustion are significant only when acid ions additives are present.

Oxidation of lignans and lignin model compounds by laccase in aqueous solvent systems

Abstract: The stability and activity of the low redox potential Melanocarpus albomyces laccase (MaL) in various aqueous organic (acetone, ethanol, propylene glycol, diethylene glycol monomethyl ether) solvent systems was studied spectrophotometrically using 2,6-dimethoxyphenol (2,6-DMP) as substrate. In addition, reactivity of the enzyme with two lignans; matairesinol (MR) and 7-hydroxymatairesinol (HMR), was examined by oxygen consumption measurements in the most potential aqueous organic solvent systems. Polymerization of the lignans by MaL was verified by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and size exclusion chromatography (SEC). Polymerization of the higher molecular weight lignin model compound, dehydrogenation polymers (DHPs), was studied by SEC. The solubilities of industrial softwood and hardwood kraft lignins were evaluated as parameters for investigation of enzymatic modification in aqueous organic solvent systems. The functioning of MaL in different aqueous organic media was excellent. Propylene glycol and diethylene glycol monomethyl ether were better solvents than ethanol or acetone in enzymatic oxidations. Even though they were the best solvents for enzyme oxidation, ethanol and propylene glycol were selected for further tests because of their different physicochemical properties. The results obtained in this study for the use of laccase-catalysed reactions in organic solvents to improve the efficiency of lignin oxidation may be exploited in several applications and areas in which the solubility of the reactants or products is a limiting factor.