Purines and pyrimidines are complementary bases of the genetic code. The roles of purines and their derivatives in cellular signal transduction and energy metabolism are well-known. In contrast, the roles of pyrimidines and their derivatives in cellular function remain poorly understood. In this study, the roles of uridine, a pyrimidine nucleoside, in liver metabolism are examined in mice. We r...

UNLABELLED BACKGROUND Imidazo[1,2-a]pyridines and pyrimidines are important organic fluorophores which have been investigated as biomarkers and photochemical sensors. The effect on the luminescent property by substituents in the heterocycle and phenyl rings, have been studied as well. In this investigation, series of 3-hydroxymethyl imidazo[1,2-a]pyridines and pyrimidines were synthesized an...

Early stud& with pyrimidines administered t.o animals established the fact that, these compounds arc metabolized (3, 4). Present concepts of the pathways of pyrimidine metabolism stem largely from the work of Cerecedo (4), in which he measured the changes in the urinary excretion of urea after feeding pyrimidines and related subst.ances. On the basis of these studies, he proposed an init.ial ox...

We previously identified five derivatives of Klenow fragment DNA polymerase that have lower fidelity because of amino acid substitutions in the polymerase active site. One of these has alanine substituted for the invariant Glu-710, whose side chain interacts with the deoxyribose of the incoming dNTP. Here we show that the E710A enzyme has reduced fidelity for five of the 12 possible mismatches....

Carotenoids are thought to act as antioxidants in vivo, decreasing oxidative damage to biomolecules and thus protecting against coronary heart disease and cancer. However, human intervention studies with beta-carotene have given equivocal results in terms of cancer incidence. In an alternative molecular epidemiological approach, we have employed the 'comet assay' (single cell alkaline gel elect...

Recent studies on the fate of labeled dietary purines in the rat have shown t,hat dietary adenine is a precursor of t,he adenine and of the guanine of tissue nucleic acids (l), but that guanine (2), hypoxanthine (3), and xanthine (3) are not utilized for nucleic acid synthesis. Similar experiments have shown that the pyrimidines, uracil, thymine (2), and cytosine (4) are not incorporated into t...

The apparent structural similarity between purines and pteridines has been the subject of a number of studies attempting to demonstrate a relationship between these compounds in living systems. That a relationship does, in fact, exist has been shown, not only by purine incorporation into a pteridine (l-3), but also by the ability of at least one organism (Alcaligines fuecalis) to degrade a pter...

Photolyases repair pyrimidine dimers in DNA by converting the light energy of 300- to 500-nm photons into chemical energy. Enzymes from various organisms contain two chromophore cofactors (FADH2 and either methenyltetrahydrofolate or 8-hydroxy-5-deazaflavin) that absorb the low-energy photons and initiate splitting of the cyclobutane ring by a radical mechanism. Here, we show that, in addition ...