Guanyl radical

Guanyl radical (in general also with respect to dGuo, Guo and DNA)... 

Al-Sheikhly M (1994) The reactivity of adenyl and guanyl radicals towards oxygen. Radiat Phys Chem 44 297-301... 

Jovanovic SV, Simic MG (1989) The DNA guanyl radical kinetics and mechanisms of generation and repair. Biochim Biophys Acta 1008 39-44... 

Milligan JR, Aguilera J, Nguyen JV (2001b) Redox reactivity of guanyl radicals in plasmid DNA. Int J Radiat Biol 77 281-293... 

Due to the high spin density at the heteroatoms and a correspondingly low one at carbon, the guanyl radical does not react with O2 on the pulse radiolysis time scale [75]. This low reactivity is further supported by the observation that even at the low dose rates of y-radiolysis there is merely a small uptake of O2 [G(-02) = 0.7 X 10 mol J ] when the heteroatom-centered 2 -deoxyguanosine radicals are generated by Tl in N20/02-saturated solution [121]. 

Agnihotri N, Mishra PC (2010) Formation of 8-nitroguanine due to reaction between guanyl radical and nitrogen dioxide eatalytic role of hydration. J Phys Chem B 114 7391-7404... 

W. P., Katsuki, S., Kimura, H., Guanylate cyclase activation by azide, nitro compounds, nitric oxide, and hydroxyl radical and inhibition by... 

Since hemoproteins such as lactoperoxidase and catalase are inhibited more rapidly than the sulfhydryl oxidation occurs, it is unlikely that the rapid activation of guanylate cyclase occurs by sulfhydryl oxidation [132]. Prolonged incubation of the papain or dehydrogenase enzymes with substrate and nitroprusside yielded a turbidity which indicated denaturation of the enzyme to an insoluble form, possibly by the formation of disulfide bridges via the dimerization of thiyl radicals [132]. 

Formamidine. Accdg to Hackh s (1944), p 352-L formamidine is a compd contg the bivalent —NrCH.NH— radical, while guanyl (P 391 R) is the monovalent radical —C( NH).NH3 Since the compds described below are listed in Beil, and other refs under Formamidine, we are following their nomenclature and giving the name of Guanyl as an alternate... 

Another possibility that deserves further investigation is the formation of a transient and reversible complex of nitric oxide and oxygen to yield the nitro-syldioxyl radical (ONOO ) The nitrosyldioxyl radical may be stabilized by hydrogen bonding to water, which may prevent it from activating guanylate cyclase (Beckman and Koppenol, 1992). 

Possible equilibrium involved in the rapid activation of soluble guanylate cyclase and the slower inactivation by reaction of nitric oxide with oxygen. Nitric oxide dissolved in membranes may be more stable than in solution, because the nitrosyldioxyl radical cannot be stabilized by hydrogen bonding to water. 

Nitrosothiols should not bind directly to the heme of guanylate cyclase, but rather to activate guanylate cyclase by releasing nitric oxide. The simple cleavage of nitrosothiols into nitric oxide and a thiol radical is energetically expensive, so the activation may involve an oxidation with a second thiol group. 

Rodent KC and HC, as well as human HC, express an inducible NO synthase under septic or inflammatory conditions. In vivo in endotoxemia, this expression is transient. Our in vivo data indicate that this induced -NO serves a protective role in the liver and reduces hepatic injury in endotoxemia. This protective action may be mediated by the capacity of NO to neutralize oxygen radicals and prevent platelet adherence and aggregation. Our in vitro studies show that HC-derived -NO can activate soluble guanylate cyclase. Other in vitro effects include the nonspecific suppression of protein synthesis and a small reduction in mitochondrial aconitase activity. The relevance of these in vitro actions to hepatic function in vivo remains to be determined. 

If we adopt Roman numerals for tetrazene , then the name will be (Tetrazolyl-5 ), guanyl.l, IV-tetrazene orGuanyl(tetrazolyl-5f). IV, 1-tetrazene. The figure 5 which follows the name of the tetrazoly radical, signifies that the position 5 of the tetrazolyl is connected to the tetrazene. 

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