The rates of four enzymatic processes (CDP reduction, dCMP deamination, DNA synthesis, and RNA synthesis) were measured simultaneously in intact mouse T-lymphoma (5-49) cells. Cells were treated with [“CIcytidine for 30 min before harvest and the size, radioactive content, and specific activity of all product pools analyzed by high performance liquid chromatography (including hydrolyzed RNA and...

Mitochondria from rat renal cortex were incubated with physiological concentrations of glutamate, or glutamine, or both. Changes in medium ammonia, glutamate, glutamine, and aspartate were measured and fluxes through glutamate dehydrogenase, glutaminase, and glutamate oxalacetate transaminase were calculated at different pH levels in vitro and in mitochondria from animals in which metabolic aci...

The mechanism of the intermediary metabolism of the more complex amino-acids still remains obscure. It is generally CODceded that, as far as concerns the a-amino group, deamination is accompanied by oxidation with the formation of cu-keto or cr-hydroxy derivatives of the amino-acids. While the manner of oxidation of the cyclic portions of such amino-acids as contain the benzene or other rings i...

BACKGROUND We recently showed that enzymes of the TET family convert 5-mC to 5-hydroxymethylcytosine (5-hmC) in DNA. 5-hmC is present at high levels in embryonic stem cells and Purkinje neurons. The methylation status of cytosines is typically assessed by reaction with sodium bisulfite followed by PCR amplification. Reaction with sodium bisulfite promotes cytosine deamination, whereas 5-methylc...

The HIV-1 Vif protein is essential for overcoming the antiviral activity of DNA-editing apolipoprotein B mRNA editing enzyme, catalytic polypeptide 3 (APOBEC3) cytidine deaminases. We show that naturally occurring HIV-1 Vif point mutants with suboptimal anti-APOBEC3G activity induce the appearance of proviruses with lamivudine (3TC) drug resistance-associated mutations before any drug exposure....

Hydrolytic deamination of cytosines in DNA creates uracil and, if unrepaired, these lesions result in C to T mutations. We have suggested previously that a possible way in which cells may prevent or reduce this chemical reaction is through the binding of proteins to DNA. We use a genetic reversion assay to show that a restriction enzyme, PspGI, protects cytosines within its cognate site, 5'-CCW...

The hydrolytic deamination of cytosine and 5-methylcytosine residues in DNA appears to contribute significantly to the appearance of spontaneous mutations in microorganisms and in human disease. In the present work, we examined the mechanism of cytosine deamination and the response of the uncatalyzed reaction to changing temperature. The positively charged 1,3-dimethylcytosinium ion was hydroly...

Little is known about the evolution of repeated sequences over long periods of time. Using two independent approaches, we show that the majority of the repeats found in the Arabidopsis thaliana genome are ancient and likely to derive from the retention of fragments deposited during ancestral bursts that occurred early in the Brassicaceae evolution. We determine that the majority of young repeat...