Adsorption of guanine and guanosine at the pyrolytic graphite electrode
69
Citation
13
Reference
10
Related Paper
Citation Trend
Keywords:
Pyrolytic carbon
Pyrolytic graphite was cleaved in a high vacuum to obtain clean surfaces, and the secondary electron emission properties of these surfaces were determined. Pyrolytic graphite has a maximum secondary emission yield of 1.0 at 300-eV primary electron energy for electrons incident normal to the basal plane. The most probable energy of the emitted secondaries is 2 eV, with one-half of the secondaries having energy in excess of 8 eV. A maximum secondary emission yield of 0.75 at 350-eV primary energy was measured for normal incident electrons on a face that was perpendicular to the basal plane. The backscattered fraction for pyrolytic graphite was found to be 0.05. No differences were observed in the secondary electron emission properties of single-crystalline pyrolytic graphite and pyrolytic graphite that was less well ordered.
Pyrolytic carbon
Secondary emission
Secondary electrons
Cite
Citations (9)
Abstract A convenient synthesis of 9-(2-hydroxyethoxymethyl)guanine (acyclovir) from guanosine by chemical transpurination was developed. The isomerization of the 7-isomer to the desired 9-isomer and the purification of the 9-isomer was achieved simply by concentration, heating and further crystallization.
Cite
Citations (21)
Intermediates in the browning reaction of triose reductone with guanine, guanosine or guanylic acid.
The intermediates in the browning reaction of triose reductone (I) with guanine, guanosine, 2'(3')- or 5'-guanylic acid were isolated. The reaction of I with guanine in 4 N HCI at 65°C for about 1 hr produced only a brown tricyclic compound, 1, N2-(2-hydroxypropenylidene)-guanine or 7-hydroxy-10-oxo-9, 10-dihydropyrimido[1, 2-a] purine (III) with the analogous structure to natural occurring Y bases, whereas that at room temperature yielded a labile light yellow intermediate, N2-(3-oxo-2-hydroxypropenyl)guanine (II) with the enaminol structure as a mixture with III. The ratio of II to III was about 1:1. The isolation of II in pure form was difficult because of its instability. On the other hand, the reaction of I with guanosine, 2'(3')- or 5'-guanylic acid in 4 N HCl at room temperature gave the reductive intermediate with the same enaminol structure as II, N2-(3-oxo-2-hydroxypropenyl)guanosine (IV), N2-(3-oxo-2-hydroxypropenyl) 2' (3')-guanylic acid (V) or N2-(3-oxo-2-hydroxypropenyl) 5'-guanylic acid (VI), respectively.
Guanosine monophosphate
Cite
Citations (2)
Cite
Citations (70)
Abstract— The uptake of [ 14 C]guanine and some of its [ 14 C]‐labelled derivatives into rat brain was studied in vivo and in vitro. In vivo guanine, guanosine, and hypoxanthine penetrated the brain of adult rats to a very small extent. Inosine was taken up somewhat better. In young animals, also, guanosine was taken up poorly, but guanine was taken up fairly well. When guanine was administered to adult animals, only guanine was found in the brain. In young animals, by contrast, radioactivity from guanine appeared in guanosine and in guanine nucleotides, but no free guanine was found. In vitro guanine was taken up much better and, in fact, remained mostly as guanine in slices from 10‐day‐old rats. The in vitro conversion of guanine to GMP and its incorporation into RNA was unimpaired by the addition of unlabelled guanosine, an indication that guanine was converted directly to GMP. The uptake of guanine in vitro was not subject to competitive inhibition or influenced by the presence of dinitrophenol. This finding suggested that guanine entered the slice by simple diffusion.
Hypoxanthine
Inosine
Xanthine
Cite
Citations (22)
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Cite
Citations (0)
These studies examined the structural specificity for guanine nucleotide-facilitated hormonal activation and guanine nucleotide stabilization of cardiac adenylate cyclase. 1. The phosphonate analogues of GTP, p[CH2]ppG (guanosine 5′-[βγ-methylene]-triphosphate) and pp[CH2]pG (guanosine 5′-[αβ-methylene]triphosphate), were the most effective activators of adenylate cyclase. Other nucleotides producing significant activation (P<0.01) were, in decreasing order of activation: ITP, GDP, GMP, GTP, XTP, CTP, p[NH]ppG (guanosine 5′-[βγ-imido]triphosphate), dGTP and 2′-O-methyl-GTP. Guanosine, cyclic GMP, UTP and ppppG (guanosine tetraphosphate) had no effect, and 7-methyl-GTP caused a decrease in the activity. 2. Preincubation of membranes at 37°C for 15min before assay at 24°C produced an 80% decrease in adenylate cyclase activity, and preincubation with p[CH2]ppG and pp[CH2]pG protected and resulted in a net increase in activity. Other nucleotides that completely or partially preserved activity in decreasing order of effectiveness were p[NH]ppG, GDP, GTP, dGTP, ITP, ppppG, 2′-O-methyl-GTP, GMP, CTP and XTP. Several compounds had no effect, including guanosine, cyclic GMP and UTP, whereas preincubation with 7-methyl-GTP produced a further decrease (P<0.05) in activity. 3. The concentration-dependence for activation and stabilization by the naturally occurring guanine nucleotides was examined in the absence of a regenerating system and revealed GMP to have no stabilizing effect and to be less potent than either GDP or GTP in activating adenylate cyclase. 4. A significant correlation (r=0.90) was found between the properties of activation and stabilization for the compounds examined. These findings are consistent with there being a single nucleotide site through which both the activation and stabilization of adenylate cyclase are mediated.
Guanosine diphosphate
Cite
Citations (5)
Inosine
Cite
Citations (25)
A platinum(IV) complex with a high reduction potential, d,l-1,2-diaminocyclohexyltetrachloroplatinum(IV) (PtIV(dach)Cl4), oxidizes guanine in guanosine-5'-monophosphate (GMP), 2'-deoxyguanosine-5'-monophosphate (dGMP), d(GG), and a double-stranded oligonucleotide to 8-oxo-guanine. To the best of our knowledge, this is the first report that provides unambiguous evidence of DNA oxidation by a PtIV complex. This oxidative damage may differentiate the anticancer activity of PtIV complexes from their PtII analogues.
Deoxyguanosine
Guanosine monophosphate
Cite
Citations (35)