The role of nucleotides as precursors of ribonucleic acid in animal tissues has been well documented (l-4). ilside from the formation of polymers by the enzyme polynucleotide phosphorylase (5), only one preliminary report of net synthesis of polyribonucleotides in cell-free systems has been made (6). Hilmoe and Heppel (7) have demonstrated the phosphorolysis of added polyadenylic acid by a part...

Cytochrome P-450 (CYP) 2E1, the alcohol-inducible form of CYP, metabolizes a wide variety of endogenous substrates, therapeutic agents, protoxicants, and procarcinogens. CYP2E1 levels are posttranscriptionally elevated in response to certain xenobiotic inducers (e.g., pyridine), and proposed mechanisms include increased translational efficiency and protection of the enzyme from ubiquitin-depend...

where the expression following the first equality is the force in the spring and that following the second is the frictional resistance to sliding of the block (both expressed for a block of unit area). The load point velocity vo is the product of the imposed rate of tectonic strain rate γ̇ in the crustal block and the characteristic length of the block. The effective spring stiffness k is the s...

The authors demonstrate a smart and versatile approach for preparing multi-spectral conjugated polymers from a commercial precursor MEH-PPV without tedious synthetic modification. Multi-color CPNs with small size have also been successfully prepared using a modified-reprecipitation procedure for live cell imaging.

Subcellular-fractionation studies confirmed previous findings that rat liver glycerol phosphate acyltransferase was located in both mitochondria and the microsomal fraction. Studies of the two activities revealed several differences between them. The mitochondrial enzyme had a lower Km for sn-glycerol 3-phosphate and was more resistant to heat inactivation than was the microsomal enzyme. Some p...

Glutathione S-transferase is present in rat liver microsomal fraction, but its activity is low relative to the transferase activity present in the soluble fraction of the hepatocyte. We have found, however, that the activity of microsomal glutathione S-transferase is increased 5-fold after treatment with small unilamellar vesicles made from phosphatidylcholine. The increase in activity is due t...

1. Inhibition of endogenous microsomal NADPH oxidase by CO enables membranebound glutathione-insulin transhydrogenase (EC 1.8.4.2) to be assayed conveniently by a linked assay involving NADPH and glutathione reductase (EC 1.6.4.2). 2. The specific activity of the enzyme in rat liver microsomal preparations is of the order of 1 nmol of oxidized glutathione formed/min per mg of membrane protein. ...