Comparing growing and density-inhibited cultures of mouse 3T3 cells, we have determined that when cells became density-inhibited: 1. The sizes of the ribonucleotide pools and of the inorganic and organic phosphate pools dropped only slightly, if at all. 2. The sizes of the deoxyribonucleotide pools dropped several-fold. 3. The rate of 32POq transport across the cell membrane declined 5-fold. 4....

The diphosphate of the antiherpetic agent acyclovir [9-[(2-hydroxyethoxy)methyl]guanine] has been shown to inhibit purine nucleoside phosphorylase with unique potency (Tuttle, J. V., and Krenitsky, T. A. (1984) J. Biol. Chem. 259, 4065-4069). A major factor contributing to the superior inhibition by this diphosphate over the corresponding mono- and triphosphates is revealed here. Homologues of ...

The solution complexes of ethidium bromide with nine different deoxydinucleotides and the four self-complementary ribodinucleoside monophosphates as well as mixtures of complementary and noncomplementary deoxydinucleotides were studied as models for the binding of the drug to DNA and RNA. Ethidium bromide forms the strongest complexes with pdCdG and CpG and shows a definite preference for inter...

Bacteriophage T4 gene 44/62 and 45 accessory proteins stimulate DNA synthesis by T4 DNA polymerase. Using a @X174 DNA template primed with a strand of a restriction fragment, these accessory proteins also greatly increase the hydrolysis of dNTP to dNMP which accompanies DNA synthesis by the polymerase. The rate of formation of a deoxynucleoside monophosphate is up to 10 times the rate of its in...

We have cloned the gene for polyphosphate:AMP phosphotransferase (PAP), the enzyme that catalyzes phosphorylation of AMP to ADP at the expense of polyphosphate [poly(P)] in Acinetobacter johnsonii 210A. A genomic DNA library was constructed in Escherichia coli, and crude lysates of about 6,000 clones were screened for PAP activity. PAP activity was evaluated by measuring ATP produced by the cou...

We have demonstrated that acylphosphatase possesses ATP-diphosphohydrolase (apyrase-like) activity. In fact, acylphosphatase first catalyses the hydrolysis of the gamma-phosphate group of nucleoside triphosphates, and then attacks the beta-phosphate group of the initially produced nucleoside diphosphates, generating nucleoside monophosphates. In contrast, it binds nucleoside monophosphates but ...

the interaction of magnesium hydrate at the phosphate oxygen atom of the pyrimidine nucleotides (cmp,ump,dtmp) were studied at the hartree-fock level theory. we used lanl2dz basis set for mg and 6-31g* basis set for atoms.the basis set superposition error (bsse) begins to converge for used method/basis set. the gauge-invariant atomic orbital (giao) method and the continuous-set-of-gauge-transfo...