The basic properties of estradiol 2-hydroxylase in rat brain microsomes were studied and compared to the known characteristics of rat liver microsomal estradiol 2-hydroxylase. Rat liver microsomal estradiol 2-hydroxylase, which has been considered to be a cytochrome P450-like enzyme, was largely inhibited by carbon monoxide. On the other hand, the effect of carbon monoxide on the activity of ra...

The metabolic activation of the prohormone vitamin D(3) requires a 25-hydroxylation that has been reported to be catalyzed by both mitochondrial CYP27A and a microsomal vitamin D(3) 25-hydroxylase in the liver. CYP27A has been extensively studied, but its role as a physiologically important vitamin D(3) 25-hydroxylase has been questioned. The present paper reports that the microsomal vitamin D(...

In some donor-acceptor blends based on conjugated polymers, a pronounced charge-transfer complex (CTC) forms in the electronic ground state. In contrast to small-molecule donor-acceptor blends, the CTC concentration in polymer:acceptor solution can increase with the acceptor content in a threshold-like way. This threshold-like behavior was earlier attributed to the neighbor effect (NE) in the p...

In this study, electroabsorption (Stark) spectroscopy is used to determine the trace of the change in polarizability (Tr α ∆ ) and the absolute value of the change in dipole moment ( μ ∆ ) of the electroluminescent polymer MEH-PPV and several model oligomers in solvent glass matrices. We find a value of Tr α ∆ of ~ 2000 Å for the polymer and for a 9-ring substituted oligomer in both toluene and...

This work demonstrates the comparative studies of non-radiative resonance energy transfer in bi-polymer nanoparticles based on fluorescent conjugated polymers. For this purpose, poly[(9,9-dihexylfluorene) (PF) as a donor (D) and poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) as an acceptor (A) have been utilized, from which four different bi-polymer nanoparticle systems ...

Paraoxon, the main active metabolite of the organophosphorus insecticide parathion, exerted a dose-dependent inhibitory effect on the activity of pig kidney (Na+ + K+)-ATPase contained in microsomal fraction and purified from it. Substrate kinetics studies revealed the existence of two active sites with high and low affinity to ATP. The Dixon analysis of the mode of the inhibition indicated its...

Rats were given a single dose of toxaphene (120 mg/kg, equivalent to 1/2 LD50) and sacrificed at 1, 5, and 15 days. Liver weight and hepatic microsomal enzyme activity were increased at day 5 and 15. The level of plasma testosterone was significantly decreased at day 15. In a second experiment rats were given 2.4 mg/kg daily and sacrificed at 1, 3 and 6 months. Liver weight and microsomal enzym...

Recent observations from this laboratory have revealed that there is an alteration in the kinetic properties of microsomal glucose 6-phosphatase in the livers of diabetic rats (1, Z), in addition to the’well established increase in total activity (3, 4). Since the kinetic differences between the normal and the diabetic enzyme disappeared upon disruption of the microsomes (Z), it seemed possible...

A rapid and sensitive indirect enzyme-linked immunosorbent assay (ELISA) was developed for microsomal epoxide hydrolase of rat liver. The assay, which is easily and readily performed, is significantly more sensitive than most enzymatic epoxide hydrolase assays routinely used and electroimmunoassays previously developed. The limit of sensitivity of the ELISA is between 2-5 ng of microsomal epoxi...