It has a single ring (called a pyrimidine ring) with alternating carbon and nitrogen atoms. The molar mass of pyrimidine is 80.088 g/mol and its melting point is at 20-22 °C. Cytosine, Thymine, and Uracil Cytosine, thymine, and uracil are pyrimidine nucleobases. Cytosine can be ...
a weakly basic organic compound C4H2N2 of penetrating odor that is composed of a single six-membered ring having four carbon atoms with nitrogen atoms in positions one and three a derivative of pyrimidine having its characteristic ring structureespecially: a base (as cytosine, thymine, or uracil...
Purines, like adenine (A) and guanine (G), have a double-ringed structure consisting of a fused imidazole and pyrimidine ring. This makes them larger and more complex molecules. On the other hand, pyrimidines, such as cytosine (C), thymine (T), and uracil (U), have a single six-mem...
In addition, the single-crystal X-ray structure in a similar group of pyrazolylpyridines-Fe complexes was elucidated [107]. Sign in to download hi-res image Fig. 30. Initial hits 81 and 82 determined from a high-throughput screening campaign leading to new antitubercular agents 83–88 ...
is that the above three reactions are catalyzed by a multienzyme that incorporates the three enzymes as domains in a single polypeptide named the CAD enzyme (from a fusion of the names of the individual enzymes: carbamoyl phosphate synthase, aspartate carbamoyltransferase, and dihydroorotase). Similarl...
ring structure comprising 5 or 6 ring atoms wherein the heteroaryl ring comprises a single O ring heteroatom, a single N ring heteroatom, a single S ring heteroatom, a single O and a single N ring heteroatom separated by a carbon atom, a single S and a single N ring heteroatom separated...
DNA and RNA differ in three basic ways. First, the sugar in DNA is deoxyribose, while that in RNA is ribose; the difference between these is that deoxyribose contains one fewer oxygen atom outside the central ring. In addition, DNA is almost always double-stranded, while RNA is single-str...
The enzyme binds to DNA and introduces a transient single-strand break, unwinds the double helix (or allows it to unwind) and subsequently reseals the break before dissociating from the DNA strand. Topisomerase II has a similar mechanism of action which involves the induction of DNA strand ...
Under acidic conditions, the 1,2-dihydropyrimidine ring of intermediate 1194 can be easily opened. One of such open forms is structure 1195. Among many tautomeric forms of species 1195, there are structures with a single bond between the carbon atoms, which allow free rotation to bring the ...
The enzyme combines the function of a glycosylase, an AP-lyase and a 5′-terminal deoxyribosephosphate excising activity, thus converting the DNA base damage into single-strand breaks (Tchou et al., 1991; Boiteux et al., 1992). DNA binding is mediated by a single zinc fin...