Tricylic antidepressants acutely decrease the neuronal retention of C3H]-norepinehrine (C3H]-NE) by blocking neuronal membrane uptake and/or vesicular uptake and binding. To distinguish between effects upon the plasma membrane and upon the vesicular membrane, the retention, deamination. and O-methylation of [jH]-NE by rat brain slices were investigated in the presence of several antidepressant ...

Fumonisins are mycotoxins of world-wide distribution in maize infected by the fungus Fusarium verticillioides. They are highly toxic to certain livestock and are potential carcinogens. Exophiala spinifera, a black yeast fungus found on moldy maize kernels, was identified previously as capable of growing on fumonisin B1 as a sole carbon source and thus is a potential source for fumonisin detoxif...

The severely diabetic subject has an excessive protein metabolism which returns to normal when sufficient carbohydrate utilization is reestablished. The current hypothesis to explain this is that restoration of the ability to oxidize carbohydrate spares protein, and the metabolism returns to normal. An alternative hypothesis, namely that insulin has a direct specific effect on protein metabolis...

Thrombin-stimulated platelet secretion is accompanied by a 30% reduction in the steady state level of cytosolic ATP, a breakdown that proceeds through ADP, AMP, IMP, and inosine to hypoxanthine. The ATP to hypoxanthine conversion could be blocked at the stage of AMP deamination by incubation of platelet-rich plasma for 6 h with 200 microM coformycin, a transition-state analog inhibitor of AMP d...

The metabolism of tresperimus, a new immunosuppressive agent, was investigated in vivo and in vitro in rat and in human. Two metabolic pathways were identified at each side of the molecule with two deamination reactions on the spermidine moiety and hydrolysis of the amide bond leading to the liberation of guanidinohexylamine. As the major metabolic pathway of the drug seemed to be the oxidative...

OsO4 selectively forms thymine glycol lesions in DNA. In the past, OsO4-treated DNA has been used as a substrate in studies of DNA repair utilizing base-excision repair enzymes such as DNA glycosylases. There is, however, no information available on the chemical identity of other OsO4-induced base lesions in DNA. A complete knowledge of such DNA lesions may be of importance for repair studies. ...

The formation of new transcription factor-binding sites (TFBSs) has a major impact on the evolution of gene regulatory networks. Clearly, single nucleotide mutations arising within genomic DNA can lead to the creation of TFBSs. Are molecular processes inducing single nucleotide mutations contributing equally to the creation of TFBSs? In the human genome, a spontaneous deamination of methylated ...

Cell-free extracts prepared from rat kidney or liver catalyzed the oxidative deamination of S-adenosyl-Lhomocysteine to S-adenosyl-y-thio-a-ketobutyrate. This reaction was found to be catalyzed by L-amino acid oxidase (L-amino acid:oxygen oxidoreductase (deaminating), EC 1.4.3.2). In the presence of catalase, 0.48 pmole of oxygen was consumed for each micromole of substrate oxidized, and 1 pmol...

We have synthesized structural analogs of a natural RNA editing substrate and compared editing reactions of these substrates by recombinant ADAR-2, an RNA-editing adenosine deaminase. Deamination rates were shown to be sensitive to structural changes at the 2[prime]-carbon of the edited adenosine. Methylation of the 2[prime]-OH caused a large decrease in deamination rate, whereas 2[prime]-deoxy...