Basil extract inhibits the sulfotransferase mediated formation of DNA adducts of the procarcinogen 1′-hydroxyestragole by rat and human liver S9 homogenates and in HepG2 human hepatoma cells

The effects of a basil extract on the sulfation and concomitant DNA adduct formation of the proximate carcinogen 1′-hydroxyestragole were studied using rat and human liver S9 homogenates and the human hepatoma cell line HepG2. Basil was chosen since it contains the procarcinogen estragole that can be metabolized to 1′-hydroxyestragole by...

Identification of 14 quercetin phase II mono- and mixed conjugates and their formation by rat and human phase II in vitro model systems

In this study, the HPLC, UV-vis, LC-MS, and 1H NMR characteristics of 14 different phase II mono- and mixed conjugates of quercetin were determined, providing a useful tool in the identification of quercetin phase II metabolite patterns in various biological systems. Using these data, the phase II metabolism of quercetin by different rat and...

Inhibition of zaleplon metabolism by cimetidine in the human liver: In vitro studies with subcellular fractions and precision-cut liver slices

The effect of cimetidine on the metabolism of zaleplon (ZAL) in human liver subcellular fractions and precision-cut liver slices was investigated. 2. ZAL was metabolized to a number of products including 5-oxo-ZAL (M2), which is known to be formed by aldehyde oxidase, N-desethyl-ZAL (DZAL), which is known to be formed by CYP3A forms, and N...

Subcellular differences in post-translational modification of barley 14-3-3 proteins

Expression and post-translational modification of barley 14-3-3 isoforms, 14-3-3A, 14-3-3B and 14-3-3C, were investigated using isoform-specific antibodies. Although all three isoforms were shown to be present in the cytosolic, the nuclear and the microsomal cell fractions, differences in post-translational modification were identified for the...

Conjugation of isoprene monoepoxides with glutathione, catalyzed by α, μ, π and θ-class glutathione S-transferases of rat and man

In the present study, the enzymatic conjugation of the isoprene monoepoxides 3,4 epoxy-3-methyl-1-butene (EPOX-I) and 3,4-epoxy-2-methyl-1-butene (EPOX-II) with glutathione was investigated, using purified glutathione S-transferases (GSTs) of the α, μ, π and θ-class of rat and man. HPLC analysis of incubations of EPOX-I and EPOX-II with [35S...

Characterization of phospholipase A2 activity enriched in the nerve growth cone

Nerve growth cones isolated from fetal rat brain exhibit in their cytosol a robust level of phospholipase A2 activity hydrolyzing phosphatidylinositol (PI) and phosphatidylethanolamine (PE) but not phosphatidylcholine (PC). Western blot analysis with an antibody to the well- characterized cytosolic phospholipase A2 (mol wt 85, 000) reveals only...

A sensitive ELISA for human tissue-type plasminogen activator applicable to the study of acute release from cultured human endothelial cells

The development of a highly sensitive, enzyme-linked immunosorbent assay (ELISA) for tissue-type plasminogen activator (tPA) is described. The use of a biotin-avidin system resulted in a detection limit of 10 pg of tPA per ml, which is 50 to 150 times more sensitive than commercially-available ELISAs. Free tPA and tPA complexed to PA inhibitor...

Subcellular localization of newly formed [3H]acetylcholine in rat cerebral cortex in vitro

Slices from rat brain cortex were incubated for either 5 or 60 min in a medium containing [3H]choline and 4.7 or 25 mM KCl. Bioassayable ACh and labelled ACh were determined in the incubation medium, in the total tissue homogenate and in subcellular fractions. Raising the KCl concentration from 4.7 to 25 mM stimulated the release and synthesis...