The gas phase acidities of a series of uracil derivatives (1-methyluracil, 3-methyluracil, 6-methyluracil, 5,6-dimethyluracil, and 1,3-dimethyluracil) have been bracketed to provide an understanding of the intrinsic reactivity of uracil. The experiments indicate that in the gas phase, uracil has four sites more acidic than water. Among the uracil analogs, the N1-H sites have deltaH(acid) values...

PURPOSE This study determined the effect of different weekly dosing schedules of 5-fluorouracil (5-FU)/leucovorin (LV)/eniluracil on dihydropyrimidine dehydrogenase (DPD) activity and plasma uracil levels. METHODS Plasma and mononuclear cells were isolated from peripheral blood samples obtained before, during, and at various times after 5-FU/LV/eniluracil therapy. Two schedules were studied: ...

We have purified uracil DNA-glycosylase (UDG) from calf thymus 32,000-fold and studied its biochemical properties, including sequence specificity. The enzyme is apparently closely related to human UDG, since it was recognised by a polyclonal antibody directed towards human UDG. SDS-PAGE and western analysis indicate an apparent M(r) = 27,500. Bovine UDG has a 1.7-fold preference for single stra...

Male F344 rats were given a diet supplemented with uracil at concentrations of 1 or 3% for 15 or 30 wk. In the group given 3% uracil, numerous calculi of uracil were observed in the urinary tract with marked hyperplasia and papillomas of the urinary bladder mucosa in Wk 15 and 30. In Wk 30, dysplasia of the ureteral mucosa and one transitional cell carcinoma of the bladder were also found. Neit...

Excision of uracil from tetraloop hairpins and single stranded ('unstructured') oligodeoxyribonucleotides by Escherichia coli uracil DNA glycosylase has been investigated. We show that, compared with a single stranded reference substrate, uracil from the first, second, third and the fourth positions of the loops is excised with highly variable efficiencies of 3.21, 0.37, 5.9 and 66.8%, respecti...

The 1,4-dihydro-pyridine ring in the title compound, C(17)H(19)NO(5), has a flattened-boat conformation, and the benzene ring is almost orthogonal to it [dihedral angle = 82.98 (12)°]. The hydr-oxy group is disordered over two positions in a 0.780 (4):0.220 (4) ratio. In the crystal, hydrogen-bonding inter-actions of the type N(a)-H⋯O(c) and O(h)-H⋯O(c) (a = amine, c = carbonyl and h = hydr-oxy...

Archaeal family-B DNA polymerases bind tightly to deaminated bases and stall replication on encountering uracil in template strands, four bases ahead of the primer-template junction. Should the polymerase progress further towards the uracil, for example, to position uracil only two bases in front of the junction, 3'-5' proof-reading exonuclease activity becomes stimulated, trimming the primer a...

The association of uracil dimers and copper(II) has been studied through the use of B3LYP/6-311+G(3df,2p)//6-31+G(d,p) calculations. Although uracil-Cu(2+) complexes have never been experimentally detected, our results show that [(uracil)2-Cu](2+) is thermodynamically stable with regard to both the proton loss and the fragmentation into (uracil)2(+)˙ + Cu(+), although it is metastable with resp...