We demonstrate for the first time the combination of human liver cytosol and microsomal enzyme sources into an electro-optical array to screen for reactive metabolites produced in multi-enzyme metabolic processes.

Squalene epoxidase activity has been studied in cell-free preparations of Chinese hamster ovary (CHO) cells and rat liver. In contrast to rat liver microsomal squalene epoxidase, the enzyme of CHO cells is only slightly activated by the autologous cytosolic fraction, whereas phosphatidylglycerol or rat liver cytosolic preparations are potent stimulators of this enzyme. Triton X-100, a known sti...

In a previous study on heparin biosynthesis, incubation of a mouse mastocytoma microsomal fraction with UDP-N-acetyl-D-glucosamine and UDP-D-glucuronic acid resulted in the formation of two nonsulfated polysaccharides, one of which was fully N-acetylated whereas the other contained about equal amounts of Nacetylated and N-unsubstituted glucosamine residues. In the presence of 3’-phosphoadenylyl...

In a previous study on heparin biosynthesis, incubation of a mouse mastocytoma microsomal fraction with UDP-N-acetyl-D-glucosamine and UDP-D-glucuronic acid resulted in the formation of two nonsulfated polysaccharides, one of which was fully N-acetylated whereas the other contained about equal amounts of Nacetylated and N-unsubstituted glucosamine residues. In the presence of 3’-phosphoadenylyl...

objective(s): particularly in developing countries, selenium and/or iodine deficiencies are encountered and use of pesticides in agriculture are not well-controlled. fenvalerate is a pyrethroid insectide used in agriculture and has applications against a wide range of pests. this study was designed to evaluate the effects of fenvalerate on hepatic and cerebral xenobiotic metabolizing enzyme act...

The activity of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (hydroxymethylglutaryl-CoA reductase) was considerably inhibited during incubation with ATP + Mg2+. The inactivated enzyme was reactivated on further incubation with partially purified cytosolic phosphoprotein phosphatase. The inactivation was associated with a decrease in the apparent Km of the reductase for hydroxymethylglutaryl-...

Renal Na-K-ATPase activity changes adaptively in response to chronic alterations in sodium reabsorption or potassium secretion, but the role of this enzyme in rapid adjustments of renal tubular Na and K transport is not known. To evaluate this question, microsomal Na-K-ATPase specific activity and kinetics were determined in the rat and guinea pig kidney after massive but short-term (3 h) sodiu...

Under anaerobic conditions the addition of reduced diphosphopyridine nucleotide to stoichiometric amounts of microsomal cytochrome reductase yields reduced flavin and a nucleotideenzyme complex characterized by a 315-rnp absorption peak (2). The properties of the reactive sulfhydryl groups of the enzyme and the evidence for the participation of only one such group in this reaction have been des...

The subcellular distribution of arylamidases in rat liver and rat kidney was studied. Lysosomes prepared from both tissues had the highest concentration of arylamidases. Different types of arylamidases have been found in the lysosomes and microsomes of these tissues. The lysosomal enzymes were inhibited by divalent metal ions, lost activity on storage, were inhibited by p-chloromercuribenzoate,...