Guanine 6-thio

Guanine, 9-/3-D-ribofuranosyl-, 5, 536 Guanine, 6-thio-tautomerism, 5, 509 toxicity, 1, 141 Guanine, 8-trifluoromethyl-synthesis, 5, 574 Guanines, thio-synthesis, 5, 572 Guanosine arylation, 5, 538 dipole moment, 5, 522 free radical alkylation, 5, 543 hydrobromide... 

Schmiegelow K, Bruunshuus I. 6-Thio-guanine nucleotide accumulation in red blood cells during maintenance chemotherapy for childhood acute lymphoblastic leukemia, and its relation to leukopenia. Cancer Chemother Pharmacol 1990 26 288-292. 

Fig. 13.1 Pathways of thiopurine metabolism. The positions of two polymorphically expressed enzymes, TPMT (thiopurine methyl transferase) and ITPA (inosine triphosphate pyrophosphatase), are shown. HGPRT, hypoxanthine guanine phosphoribosyl transferase 6-TIDP, 6-thioi-nosine diphosphate 6-TIMP, 6-thioinosine monophosphate 6-TITP, 6-thio inosine trinophosphate...

Gamer, R.C. Campbell, J. (1985) Tests for the induction of mutations to ouabain or 6-thio-guanine resistance in mouse lymphoma L5178Y cells. In Ashby, J., de Series, F.J., Draper, M., Ishidate, M., Jr, Margolin, B.H., Maher, B.E. Shelby, M.D., eds, Progress in Mutation Research, Volume 5, Evaluation of Short-Term Tests for Carcinogens. Report of the International Programme on Chemical Safety s Collaborative Study on in vitro assays, Amsterdam, Elsevier Science, pp. 525-529... 

Gamer, R. C. Campbell, J. (1985) Tests for the induction of mutations to ouabain or 6-thio-guanine resistance in mouse lymphoma L5178Y cells. Prog. Mutat. Res., 5, 525-529... 

Nishi, Y., Hasegawa, M.M., Taketomi, M., Ohkawa, Y. Inui, N. (1984) Comparison of 6-thio-guanine-resistant mutation and sister chromatid exchanges in Chinese hamster V79 cells with forty chemical and physical agents. Cancer Res., 44, 3270-3279... 

Tates, A.D., van Dam, F.J., de Zwart, F.A., van Teylingen, C.M.M. Natarajan, A.T. (1994) Development of a cloning assay with high cloning efficiency to detect induction of 6-thio-guanine-resistant lymphocytes in spleen of adult mice following in vivo inhalation exposure to 1,3-butadiene. Mutat. Res., 309, 299-306... 

In general terms, both steric effects and electronic factors are expected to play a role in determinating the reactivity of square-planar platinum complexes. The presence of planar amine ligands in cis- or /ran.y-Pt(anion )2 complexes and their orientation with respect to the coordination plane, as well as their substituents, can reduce the rates of DNA binding or thio binding compared to aliphatic ammine and amine complexes. Especially, substituents close to the coordination site should be expected to slow down axial substitution reactions at Pt. As there is now little doubt that DNA platina-tion is a key event (or THE key event) in the mechanism of action of platinum anticancer drugs, attention to the process of formation of the major adduct (GG) as an intrastrand cross-link between N(7) atoms of two adjacent guanine (G) residues, will remain important. 

Neubig, R.R. Sklar, L.A. Subsecond modulation of formyl peptide-linked guanine nucleotide-binding proteins by gua-nosine 5 -o-(3-thio)triphosphate in permeabilized neutrophils. Mol. Pharmacol. 1993, 43, 734—740. 

Broxson EH, Dole M, Wong R, Laya BF, Stork L. Portal hypertension develops in a subset of children with standard risk acute lymphoblastic leukemia treated with oral 6-thio-guanine during maintenance therapy. Pediatr Blood Cancer 2005 44(3) 226-31. 

Fig. 2 Metabolism of 6-mercaptopurine (6-MP) via xanthine oxidase (XO) to the inactive metabolite 6-thiouric acid (6-TU), thiopurine S-methyltransferase (TPMT) to the inactive metabolite 6-methylmercaptopurine (6-MMP), and hypoxanthine guanine phosphoribosyl transferase (HPRT) to 6-thioinosine monophosphate (6-TIMP) which is then further metabolized to thioguanine nucleotides (6-TGN), 6-methylmercaptopurine ribonucleotides (6-MMPR) or 6-thio-inosine triphosphate (6-thio-ITP), these all being active metabolites...

Inhibition of forskolln stimulated adenylate cyclase in membranes by guanine nucleotides can be observed when a functional Ni subunit Is present and has been shown in membranes from rat brain,34 s49 lymphoma cells, 28,66 rat adipocytes, and human platelets. This inhibition can be observed with GTP, GppNHp, or GTP-yS (guanosine 5 -(3-0-thlo)triphosphate), is blocked by GDP or GDP-gS (guanosine 5 (2-0-thio)diphosphate), and does not require the presence of an inhibitory hormone. Guanine nucleotide Inhibition of adenylate cyclase is not competitive with forskolln and is not observed when membranes are... 

Lorenzen, A., Fuss, M., Vogt, H., and Schwabe, U. (1993) Measurement of guanine nucleotide-binding protein activation by A1 adenosine receptor agonists in bovine brain membranes stimulation of guanosine-5 -0-(3-P S]thio)triphosphate binding. Mol. Pharmacol. 44, 115-123. 

Uracil and cytosine derivatives of 4-thio-DL-erythrofuranose and adenine and guanine nucleoside analogues of 4-thio-D-ribofuranose, 4-thio-D-xylofuranose, and 5-thio-D-xylopyranose have been reported. Treatment of 2,2 -anhydro-cytosine with phosphorus pentasulphide gave the cyclic thiophosphate derivatives (49), which was used to prepare other 2 -thio-cytidine derivatives. The... 

One group of compounds that have proved to be particularly effective in interfering with DNA synthesis of tumour cells are the mercapto-purines and pyrimidines and their alkyl derivatives 6-mercaptopurine (6-MP) blocks the de novo synthesis of purines 9-(jS-D-arabinofuranosyl)-—9H—purine—6-thiol (ara—6-MP) inhibits the incorporation of L-aspartic acid and orotic acid into DNA cystosine 9-OS-D-xylo-furanosyl)—9H—purine—6-thiol (xyl—6-MP) inhibits the utilization of exogenously administered guanine the periodic acid oxidation product of 9-(/S-D-ribosyl)—6-methyl—thio purine (MMPR—OP) blocks the incorporation of thymidine into DNA . The effective clinical use of thiols... 

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