A series of 11 new substituted 1,5-dihydro-4,1-benzoxazepine derivatives was synthesised to study the influence methyl group in 1-(benzenesulphonyl) moiety, replacement purine by benzotriazole bioisosteric analogue, and introduction a bulky substituent at position 6 purine, on biological effects. Their inhibition against isolated HER2 studied structure–activity relationships have been confirmed...

Nucleic acid duplexes containing non-Watson–Crick base pairs are of interest to several fields including structural biology, supramolecular chemistry, origin of life, and synthetic biology. An early observation of a natural non-Watson–Crick base pair was the tRNA–mRNA adenine–inosine wobble pair, and it is now known that purine–purine pairs occur frequently in natural RNAs, including ribosomes ...

The urines of two unrelated children with inherited deficiencies of purine nucleoside phosphorylase have been found to contain significant quantities of orotic acid in addition to the previously reported purine nucleosides. The data are consistent with some cell types of these immunodeficient patients being deplete of pyrophosphoribosylphosphate, a precursor of both purine, and pyrimidine nucle...

pentenyl)adenosine (IPAR). The resistance was unaltered after 5 months maintenance in absence of the drug. S-180/KR cells showed increased sensitivity to certain purine and pyrimidine nucleoside analogs such as 6-thiopurine ribonucleoside and 5-fluorodeoxyuridine. The activity of purine nucleoside phosphorylase (purine nucleoside:orthophosphate ribosyltransferase, EC 2.4.2.1) an enzyme that in ...

Hfr and F' Lac male strains of Escherichia coli were mated with purine-requiring females which had been starved for purine. These females formed mating pairs with the males. However, a mating in the absence of purine markedly reduced the yield of recombinants. Transfer of F' Lac or of lambda prophage also occurred infrequently. It was concluded that deoxyribonucleic acid transfer from male to f...

GAR transformylase, which is responsible for the incorporation of formate carbon into what becomes position 8 of the purine ring, has been completely separated from 5-amino-4-imidazolecarboxamide ribotide transformylase (3). The latter enzyme is responsible for the incorporation of formate carbon into position 2 of the purine ring. The requirement for folic acid compounds has been demonstrated ...

The flux activities of de novo and salvage purine synthesis were compared in rat hepatoma 3924A cells in various growth phases. The initial rate assays of [I4C]adenine, ("C]hypoxanthine, and |"C]guanine incorporation yielded Michaelis-Menten kinetics with A'msof 5, 7, and 7 #tM,respectively. After replating plateau phase cells in lag and log phases the activity of purine de novo pathway increas...