Estimation of guanine deaminase using guanosine as a “prosubstrate”

Roberts, Elton L.; Newton, Russell P.

doi:10.1016/j.ab.2003.09.041

Cited by 11 publications

(14 citation statements)

References 15 publications

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“…The hydrolytic deamination of guanine to xanthine is well documented: an enzyme guanine deaminase catalyses the addition of H 2 O and elimination of NH 3 [17]. There is a clear similarity with the above described phenomena in the product ion spectra of guanosine.…”

Section: In-source Generation Of the Ring-opened Protonated Xanthinementioning

confidence: 54%

In-source CID of guanosine: Gas phase ion-molecule reactions

Tuytten

Lemière

Esmans

et al. 2006

J. Am. Soc. Mass Spectrom.

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In-source collision induced dissociation was applied to access second generation ions of protonated guanosine. The in-source gas-phase behavior of [BH 2 ] ϩ -NH 3 (m/z 135, C 5 H 3 N 4 O ϩ ) was investigated. Adduct formation and reactions with available solvent molecules (H 2 O and CH 3 OH) were demonstrated. Several addition/elimination sequences were observed for this particular ion and solvent molecules. Dissociation pathways for the newly formed ions were developed using a QqTOF mass spectrometer, permitting the assignment of elemental compositions of all product ions produced. Reaction schemes were suggested arising from the ring-opened intermediate of the protonated base moiety [BH 2 ] ϩ , obtained from fragmentation of guanosine. The mass spectral data revealed that the in-source CH 3 OH-reaction product underwent more complex fragmentations than the comparable ion following reaction with H 2 O. A rearrangement and a parallel radical dissociation pathway were discerned. Apart from the mass spectrometric evidence, the fragmentation schemes are supported by density functional theory calculations, in which the reaction of the ring-opened protonated guanine intermediate with CH 3 OH and a number of subsequent fragmentations were elaborated. uring the last decade, most fragmentation pathways were elaborated on triple quadrupole (QqQ) and particularly quadrupole ion-trap (QIT) instruments. The latter's capabilities of accessing MS n product ions by applying repeated stages of mass selection and fragmentation proved to be very useful [1]. The maturation of the time of flight (TOF) technology and, more importantly, its use in hybrid-arrangements such as the popular orthogonal QqTOF mass spectrometer made accurate mass data of product ions more readily available [2]. In many cases, the elemental compositions of the product ions can unambiguously be assigned when using a QqTOF mass spectrometer. Product ions lower in the genealogical ladder are also accessible by applying relatively high collision energies in the collision cell. Yet disentanglement of different dissociation pathways originating from a communal progenitor is -in general-still confined to QIT set ups, although the interpretation of energy resolved spectra also has proven its usefulness [3].Recently we and others showed [4 -6] that by making optimal use of in-source CID, combined with the inherent tandem MS capabilities of the QqTOF, what is in effect up to MS 5 data can be acquired. Compared to QIT data the QqTOF data obtained is superior in respect of higher mass accuracy. On the other hand QIT-CID experiments, in general, access almost exclusively the dissociation reaction channels of the lowest energy of activation [7]. This energy-dependent information can

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Section: In-source Generation Of the Ring-opened Protonated Xanthinementioning

confidence: 54%

In-source CID of guanosine: Gas phase ion-molecule reactions

Tuytten

Lemière

Esmans

et al. 2006

J. Am. Soc. Mass Spectrom.

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“…On the other hand, mammalian, insect, fungal, and some bacterial GDs belong to the TIM barrel metallohydrolase superfamily (5,6). GD is the only identified enzyme in mammals that can directly deaminate a base, and its diagnostic usefulness has been well documented, for example, in the detection of hepatoma and the identification of donor blood infected with the hepatitis C virus (7,8). The expression of mammalian GDs has been shown to be tissue-specific and to fluctuate during development, and various GD activities have been found in cancerous breast and kidney tissues (9 -12).…”

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confidence: 99%

Crystal Structure of Bacillus subtilis Guanine Deaminase

Liaw

Chang

Lai³

et al. 2004

Journal of Biological Chemistry

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Guanine deaminase, a key enzyme in the nucleotide metabolism, catalyzes the hydrolytic deamination of guanine into xanthine. The crystal structure of the 156-residue guanine deaminase from Bacillus subtilis has been solved at 1.17-Å resolution. Unexpectedly, the Cterminal segment is swapped to form an intersubunit active site and an intertwined dimer with an extensive interface of 3900 Å 2 per monomer. . The closed conformation also reveals that substrate binding seals the active site entrance, which is controlled by the C-terminal tail. Therefore, the domain swapping has not only facilitated the dimerization but has also ensured specific substrate recognition. Finally, a detailed structural comparison of the cytidine deaminase superfamily illustrates the functional versatility of the divergent active sites found in the guanine, cytosine, and cytidine deaminases and suggests putative specific substrate-interacting residues for other members such as dCMP deaminases.

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“…Fenol é o composto mais utilizado mundialmente como substância precursora da reação de Berthelot (CERDÀ et al, 1995;HARFMANN;CROUCH, 1989;KILLEEN et al, 1993;ROBERTS;NEWTON, 2004;SEARCY et al, 1968). Além do fenol outros reagentes comumente utilizados são o salicilato (DEEPA et al, 2003;GONZÁLEZ-RODRIGUEZ et al, 2002;VADER et al, 2000;WANG et al, 2003) e o timol (GLEBKO et al, 1967).…”

Section: Aspectos Gerais E Aplicaçõesunclassified

“…Entre as substâncias estudadas, destacam-se os íons Mn(II) e a acetona (SEARLE, 1984). No entanto a substância mais utilizada como catalisador, há muitas décadas, em quase todos os métodos que fazem uso da reação de (CERDÀ et al, 1995;DEEPA et al, 2003;GONZÁLEZ-RODRIGUEZ et al, 2002;HARFMANN;CROUCH, 1989;KILLEEN et al, 1993;ROBERTS;NEWTON, 2004;SEARCY et al, 1968;SEARLE, 1984;STWART, 1985;WANG et al, 2003). A etapa na qual este reagente atua na reação de Berthelot ainda não é conhecida (HARFMANN; CROUCH, 1989), mas sua presença aumenta a velocidade de formação do composto colorido (SEARCY et al, 1968).…”

Section: Aspectos Gerais E Aplicaçõesunclassified

“…Entre as fontes de oxidantes mais empregadas pode-se citar o hipoclorito (CERDÀ et al, 1995;DEEPA et al, 2003;GONZÁLEZ-RODRÍGUEZ et al, 2002;KILLEEN et al, 1993;ROBERTS;NEWTON, 2004;SEARCY et al, 1968;STEWART, 1985;VADER et al, 2000) e o hipobromito (GLEBKOet al, 1967). Uma solução de hipobromito apresenta estabilidade de até 4 semanas se mantida entre 4ºC e 5ºC (GLEBKOet al, 1967) e, em geral, é utilizada quando o composto fenólico é o timol (SEARLE, 1984).…”

Section: Aspectos Gerais E Aplicaçõesunclassified

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Estudos da modificação da resina não-iônica Amberlite XAD-7 com monoetanolamina (MEA) para retenção de espécies de S(IV)

Ferreira¹

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"...De tudo ao meu amor, serei atento antes, e com tal zelo e sempre e tanto, que mesmo em face do maior encanto, dele se encante mais meu pensamento..." Ao meu querido e amado esposo Cleber Gonçalves Ferreira, por seu amor inigualável, dedicação, companheirismo e pelos maravilhosos momentos vividos. Ser humano raro, de ações e pensamentos nobres. Aos meus queridos pais, Lia e José Carlos, por todo o amor, carinho, apoio e sabedoria nos momentos de dificuldade e por saber que sempre estarão ao meu lado, me apoiando e torcendo por mim.

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Estimation of guanine deaminase using guanosine as a “prosubstrate”

Cited by 11 publications

References 15 publications

In-source CID of guanosine: Gas phase ion-molecule reactions

In-source CID of guanosine: Gas phase ion-molecule reactions

Crystal Structure of Bacillus subtilis Guanine Deaminase

Estudos da modificação da resina não-iônica Amberlite XAD-7 com monoetanolamina (MEA) para retenção de espécies de S(IV)

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