13 research outputs found
Functional Evaluation of a Fluorescent Schweinfurthin: Mechanism of Cytotoxicity and Intracellular Quantification
3-Deoxyschweinfurthin B Lowers Cholesterol Levels by Decreasing Synthesis and Increasing Export in Cultured Cancer Cell Lines
The approximate sampling distribution of Kuder-Richardson reliability coefficient twenty
In vitro studies in a myelogenous leukemia cell line suggest an organized binding of geranylgeranyl diphosphate synthase inhibitors
Rayleigh-Based Concept to Tackle Strong Hydrogen Fractionation in Dual Isotope Analysis-The Example of Ethylbenzene Degradation by Aromatoleum aromaticum
International audienceCompound-specific isotope analysis (CSIA) is a state-of-the-art analytical tool that can be used to establish and quantify biodegradation of pollutants such as BTEX compounds at contaminated field sites. Using isotopes of two elements and characteristic Lambda values (A) in dual-isotope-plots can provide insight into reaction mechanisms because kinetic isotope effects (KIEs) of both elements are reflected. However, the concept's validity in the case of reactions that show strong isotope fractionation needs to be examined. The anaerobic ethylbenzene degradation pathway of Aromatoleum aromaticum is initiated by the ethylbenzene dehydrogenase-catalyzed monohydroxylation of the benzylic carbon atom. Measurements of stable isotope ratios revealed highly pronounced hydrogen fractionation, which could not be adequately described by the classical Rayleigh approach. This study demonstrates the nonlinear behavior of hydrogen isotope ratios caused by anaerobic ethylbenzene hydroxylation both mathematically and experimentally, develops alternative dual plots to enable the comparison of reactions by considering the reacting atoms, and illustrates the importance of the stereochemical aspects of substrate and product for the quantification of hydrogen fractionation in an enzymatic reaction. With regard to field application, proposals for an improved CSIA evaluation procedure with respect to pronounced hydrogen enrichment are given