1198-47-6Relevant articles and documents
6-Substituted 2-Aminopurine-2′-deoxyribonucleoside 5′-Triphosphates that Trace Cytosine Methylation
von Watzdorf, Janina,Marx, Andreas
, p. 1532 - 1540 (2016/09/08)
Gene expression is extensively regulated by the occurrence and distribution of the epigenetic marker 2′-deoxy 5-methylcytosine (5mC) in genomic DNA. Because of its effects on tumorigenesis there is an important link to human health. In addition, detection of 5mC can serve as an outstanding biomarker for diagnostics as well as for disease therapy. Our previous studies have already shown that, by processing O6-alkylated 2′-deoxyguanosine triphosphate (dGTP) analogues, DNA polymerases are able to sense the presence of a single 5mC unit in a template. Here we present the synthesis and evaluation of an extended toolbox of 6-substituted 2-aminopurine-2′-deoxyribonucleoside 5′-triphosphates modified at position 6 with various functionalities. We found that sensing of 5-methylation by this class of nucleotides is more general, not being restricted to O6-alkyl modification of dGTP but also applying to other functionalities.
Methylation of mercaptopurine, thioguanine, and their nucleotide metabolites by heterologously expressed human thiopurine S-methyltransferase
Krynetski, Eugene Y.,Krynetskaia, Natalia F.,Yanishevski, Yuri,Evans, William E.
, p. 1141 - 1147 (2007/10/03)
Thiopurine S-methyltransferase (TPMT), a cytosolic enzyme that exhibits genetic polymorphism, catalyzes S-methylation of mercaptopurine (MP) and thioguanine (TG), yielding S-methylated nucleobases that are inactive, whereas S-methylated nucleotides of these thiopurines are cytotoxic. A yeast- based heterologous expression system was therefore used to characterize human TPMT-catalyzed methylation of MP, TG, and their principal nucleotide metabolites [thioinosine monophosphate (TIMP) and thioguanosine monophosphate (TGMP), respectively]. MP, TG, TIMP, and TGMP were all substrates for human TPMT, exhibiting similar Michaelis-Menten kinetic parameters (K(m), 10.6- 27.1 μM; V(max), 31-59 nmol/min/mg of TPMT). Consistent with these kinetic parameters, human leukemia cells (CEM) incubated for 24 hr with 10 μM MP or TG accumulated significantly higher (2.3-fold, p = 0.01) concentrations of methyl-TIMP after MP incubation than methyl-TGMP after TG incubation, due to the 2.7-fold higher concentration of TIMP after MP incubation, compared with TG nucleotides (TGN) after TG incubation. Moreover, intracellular accumulation of TGN was 2.5-fold greater after TG incubation than after MP incubation (p = 0.01). These data establish that MP, TG, and their principal nucleotide metabolites are comparable substrates for polymorphic TPMT, and they demonstrate significant differences in the accumulation of active TGN and methylated nucleotides when leukemia cells are treated with MP versus TG.