Guanosine 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... 

Adlersberg M, Arango V, Hsiung S, Mann JJ, Underwood MD, et al. 2000. In vitro autoradiography of serotonin 5-HT (2A/2C) receptor-activated G protein guanosine-5 -(gamma-[(35)S]thio)triphosphate binding in rat brain, J Neurosci Res 61 674-685. 

The subsequent cleavage of the thio-ester succinylCoA into succinate and coenzyme A by succinic acid-CoA ligase (succinyl CoA synthetase, succinic thiokinase) is strongly exergonic and is used to synthesize a phosphoric acid anhydride bond ( substrate level phosphorylation , see p. 124). However, it is not ATP that is produced here as is otherwise usually the case, but instead guanosine triphosphate (CTP). However, GTP can be converted into ATP by a nucleoside diphosphate kinase (not shown). 

Key Words Guanosine-5 -0-(3-thio)triphosphate phosphorylation serotonin (5-hydroxytryptamine) G protein kinase receptor calmodulin phospholipase. 

Newman-Tancredi A, Cussac D, Audinot V, Pasteau V, Gavaudan S, Millan MJ (1999) G protein activation by human dopamine D3 receptors in high-expressing Chinese hamster ovary cells A guanosine-5 -0-(3-[35S]thio)-triphosphate binding and antibody study. Mol Pharmacol 55 564-574. 

Some other aspects of G protein chemistry should be noted. Thus A1F,C (fluoraluminate) can bind to G proteins forming an activated Ga GDP AIF4 complex that mimics the active Ga GTP complex. Similarly, various non-hydrolysable GTP analogues, notably guanosine-5 -[y-thio] triphosphate (GTPf y-S]), bind to Gas and cause persistent activation. [ S GTl Iy-S has been very useful for radioactively labelling Ga proteins and hence establishing that particular hormones or NTs act via a G protein-coupled mechanism. 

Another route to the preparation of deoxythioguanosine 18 from readily available deoxy-guanosine is based upon the sulfonylation of deoxyguanosine at the 6-0x0 group. This sulfony-lation activates the 6-position to addition/elimination reactions, and the sulfonyl derivative of deoxyguanosine can be converted to the thio derivative 18 under very mild conditions. 

Chopra, L.C., Twort, C.H.C., Ward, J.P.T. and Cameron, I.R (1989). Effects of heparin on inositol 1,4,5-trisphosphate and guanosine 5 -0-(3-Thio triphosphate) induced calcium... 

Griffin GR, Atkinson PJ, Showalter VM, Martin BR, Abood ME (1998) Evaluation of cannabinoid receptor agonists and antagonists using the guanosine-5 -O-(3-[35S]thio)-triphosphate binding assay in rat cerebellar membranes. J Pharmacol Exp Ther 285 553-560... 

Selley DE, Stark S, Sim LJ, ChUders SR (1996) Cannabinoid receptor stimulation of guanosine-5 -O-(3-[35S]thio)triphosphate binding in rat brain membranes. Life Sci 59 659-668 Shire D, Calandra B, Delpech M, Dumont X, Kaghad M, Fur GL, Caput D, Ferrara P (1996a)... 

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