Energetics of product formation during anaerobic degradation of phthalate isomers and benzoate
摘要:
Methanogenic enrichment cultures grown on phthalate, isophthalate and terephthalate were incubated with the corresponding phthalate isomer on which they were grown, and a mixture of benzoate and the phthalate isomer, All cultures were incubated with bromoethanosulfonate to inactivate the methanogens in the mixed culture. Thus, product formation during fermentation of the aromatic substrates could be studied. It was found that reduction equivalents generated during oxidation of the aromatic substrates to acetate were incorporated in benzoate under formation of carboxycyclohexane. During Fermentation of the phthalate isomers, small amounts of benzoate were detected, suggesting that the initial step in the anaerobic degradation of the phthalate isomers is decarboxylation to benzoate. Gibbs free energy analyses indicated that during degradation of the phthalate isomers, benzoate, carboxycyclohexane, acetate and molecular hydrogen accumulated in such amounts that both the reduction and oxidation of benzoate yielded a constant and comparable amount of energy of approximately 30 kJ mol(-1). Based on these observations it is suggested that within narrow energetic limits, oxidation and reduction of benzoate may proceed simultaneously. Whether this is controlled by the Gibbs free energy change for carboxycyclohexane oxidation remains unclear. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.
Energetics of product formation during anaerobic degradation of phthalate isomers and benzoate
摘要:
Methanogenic enrichment cultures grown on phthalate, isophthalate and terephthalate were incubated with the corresponding phthalate isomer on which they were grown, and a mixture of benzoate and the phthalate isomer, All cultures were incubated with bromoethanosulfonate to inactivate the methanogens in the mixed culture. Thus, product formation during fermentation of the aromatic substrates could be studied. It was found that reduction equivalents generated during oxidation of the aromatic substrates to acetate were incorporated in benzoate under formation of carboxycyclohexane. During Fermentation of the phthalate isomers, small amounts of benzoate were detected, suggesting that the initial step in the anaerobic degradation of the phthalate isomers is decarboxylation to benzoate. Gibbs free energy analyses indicated that during degradation of the phthalate isomers, benzoate, carboxycyclohexane, acetate and molecular hydrogen accumulated in such amounts that both the reduction and oxidation of benzoate yielded a constant and comparable amount of energy of approximately 30 kJ mol(-1). Based on these observations it is suggested that within narrow energetic limits, oxidation and reduction of benzoate may proceed simultaneously. Whether this is controlled by the Gibbs free energy change for carboxycyclohexane oxidation remains unclear. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.
Large binding constant differences between aromatic and aliphatic substrates in positively charged cavities indicative of higher order electric effects
Aliphaticsubstrates show, in comparison to aromaticsubstrates of similar shape, up to 60 times lower bindingconstants with a cyclophane bearing +N charges on the inside of the cavity; much smaller differences are observed with the same cyclophane bearing no charges in the vicinity of the substrate.
An intramolecular photoinduced electron transfer which takes place in a ZnII polyamine complex can be interrupted through coordination of a bulky carboxylate anion, acting as a curtain.
The present invention provides novel pyrimidine amines of formula I which are potent inhibitors of spleen tyrosine kinase, and are useful in the treatment and prevention of diseases mediated by said enzyme, such as asthma, COPD, rheumatoid arthritis and cancer.
The present invention provides novel pyrimidine amines of formula I which are potent inhibitors of spleen tyrosine kinase, or are prodrugs thereof, and are useful in the treatment and prevention of diseases mediated by said enzyme, such as asthma, COPD and rheumatoid arthritis and cancer.
The present invention provides novel pyrimidine amines of formula I which are potent inhibitors of spleen tyrosine kinase, or are prodrugs thereof, and are useful in the treatment and prevention of diseases mediated by said enzyme, such as asthma, COPD and rheumatoid arthritis and cancer.