Urinary nucleosides

Schram, Karl H.

doi:10.1002/(sici)1098-2787(1998)17:3<131::aid-mas1>3.0.co;2-o

Cited by 101 publications

(90 citation statements)

References 81 publications

(70 reference statements)

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“…, and nucleoside levels in urine have the potential to act as cancer biomarkers [2][3][4][5]. As their occurrence is both ubiquitous and quantitatively varying [6,7] their unequivocal characterization is crucial.For guanine alone over 20 natural variants are known to occur in RNA [6], which makes structural identification a challenging task. In our earlier LC-ESI-MS/MS experiments of urinary nucleosides [8], unexpected product ions of guanosine and its methylated derivatives were detected.…”

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confidence: 99%

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Intriguing Mass Spectrometric Behavior of Guanosine Under Low Energy Collision-Induced Dissociation: H₂O Adduct Formation and Gas-Phase Reactions in the Collision Cell

Tuytten

Lemière

Dongen

et al. 2005

J. Am. Soc. Mass Spectrom.

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An in-depth study of the fragmentation pathway of guanosine was conducted by using an in-source collision-induced dissociation high-mass accuracy tandem mass spectrometry experiment. The equivalent of MS 4 data, a level of information normally achieved on ion trap instruments, was obtained on a Q-TOF mass spectrometer. The combination of the features of high-resolution, accuracy, and in-source CID permitted the unambiguous elucidation of the different fragmentation pathways. Furthermore the elemental compositions of the product ions generated were assigned and their mutual genealogical relationships established. Formerly proposed dissociation pathways of guanosine were revisited and elaborated on more deeply. Furthermore, the presence of H 2 O in the collision cell of several tandem MS instruments was demonstrated and its effect on the product ion spectra investigated. The neutral gain of H 2 O by particular fragments of guanosine was experimentally proven by using argon, saturated with H 2 18 O, as the collision gas. Data indicating the occurrence of more complex reactions in the collision cell as a result of the presence of H 2 O were produced, specifically relating to neutral gain/neutral loss sequences. In silico calculations supported the experimental observation of neutral gain by guanosine fragments and predicted a similar behavior for adenosine. The latter was subsequently experimentally confirmed. , and nucleoside levels in urine have the potential to act as cancer biomarkers [2][3][4][5]. As their occurrence is both ubiquitous and quantitatively varying [6,7] their unequivocal characterization is crucial.For guanine alone over 20 natural variants are known to occur in RNA [6], which makes structural identification a challenging task. In our earlier LC-ESI-MS/MS experiments of urinary nucleosides [8], unexpected product ions of guanosine and its methylated derivatives were detected. The presence of these ions prompted us to perform additional mass spectrometric studies since their origin was not straightforward. This report provides an in-depth study of the fragmentation behavior of guanosine under lowenergy CID conditions, revealing H 2 O addition to specific fragments.We also wish to demonstrate the use of a Q-TOF mass spectrometer in the collection of the equivalent of MS 4 data, a level of information normally acquired only in ion trap-or FT-MS n experiments [9,10]. This was achieved by making optimal use of "in

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confidence: 99%

Intriguing Mass Spectrometric Behavior of Guanosine Under Low Energy Collision-Induced Dissociation: H₂O Adduct Formation and Gas-Phase Reactions in the Collision Cell

Tuytten

Lemière

Dongen

et al. 2005

J. Am. Soc. Mass Spectrom.

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“…The particularly high mass accuracy of this mass spectrometric method provides opportunities for identifying unknown compounds. M ore than 50 different nucleosides have been identified in urine from healthy people as well as from patients suffering from different kinds of cancer; some have been shown to be elevated in urine of cancer patients [1,2]. They are degradation products of ribonucleic acid (RNA), particularly tRNA (transfer RNA), and show various modifications [1].…”

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confidence: 99%

“…Their function and kind of modification (methylation, desaminization, conversion of uridine to pseuduridine etc.) depend on their location in the tRNA chain [1,3]. After having performed their task, the tRNA molecules are cleaved to nucleosides.…”

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“…After having performed their task, the tRNA molecules are cleaved to nucleosides. Unmodified nucleosides are recycled for biosynthesis of new RNA, while modified ones are not substrates to the salvage enzymes and thus are set free in the blood circulation and excreted with urine [1,3]. In the meantime, 79 different modified nucleosides have been isolated from tRNA and have been characterized, all of which are derivatives of the nucleosides adenosine, guanosine, uridine, and cytosine [4].…”

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MALDI-TOF MS analysis of urinary nucleosides

Kammerer¹,

Frickenschmidt²,

Gleiter³

et al. 2005

J. Am. Soc. Mass Spectrom.

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As RNA turnover seems to be impaired in cancer patients, modified nucleosides have been evaluated as potential tumor markers. Modified nucleosides are mainly formed posttranscriptionally in tRNA, set free during RNA metabolism, and excreted in urine. Especially methylated nucleosides play an important role, as their levels are higher in urine from cancer patients. For structural elucidation of known and unknown nucleosides from urine samples of cancer patients, MALDI-TOF MS and MALDI-PSD were used for the first time. This technique generally ensures high sensitivity, mass resolution, and accuracy. In our analytical approach we prepurified nucleosides from urine by affinity chromatography and subsequently separated them by semipreparative high performance liquid chromatography. The different fractions were collected separately and analyzed by MALDI-TOF MS and PSD-MALDI using a mixture of six low molecular weight calibrants for internal or external calibration. The molecular totals formulas based on a mass accuracy of 10 ppm and below were calculated and a systematic data base search was performed. The inherent problem of the MALDI-technique, the reduced sensitivity for low molecular weight substances caused by matrix suppression effects, was reduced by our technique. We identified several nucleosides in urine, which were previously identified via retention times and UV spectra of standards after HPLC analysis. Eight further nucleosides were observed. This work demonstrates for the first time the potential of MALDI-TOF and PSD-MALDI in combination with semipreparative HPLC for assignment of nucleosides in urine. The particularly high mass accuracy of this mass spectrometric method provides opportunities for identifying unknown compounds. (J Am Soc Mass Spectrom 2005, 16, 940 -947)

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Analysis of urinary nucleosides. I. Optimisation of high performance liquid chromatography/electrospray mass spectrometry

Dudley

El-Sharkawi

Games

et al. 2000

Rapid Commun. Mass Spectrom.

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Urinary nucleosides

Cited by 101 publications

References 81 publications

Intriguing Mass Spectrometric Behavior of Guanosine Under Low Energy Collision-Induced Dissociation: H₂O Adduct Formation and Gas-Phase Reactions in the Collision Cell

Intriguing Mass Spectrometric Behavior of Guanosine Under Low Energy Collision-Induced Dissociation: H₂O Adduct Formation and Gas-Phase Reactions in the Collision Cell

MALDI-TOF MS analysis of urinary nucleosides

Analysis of urinary nucleosides. I. Optimisation of high performance liquid chromatography/electrospray mass spectrometry

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Urinary nucleosides

Cited by 101 publications

References 81 publications

Intriguing Mass Spectrometric Behavior of Guanosine Under Low Energy Collision-Induced Dissociation: H2O Adduct Formation and Gas-Phase Reactions in the Collision Cell

Intriguing Mass Spectrometric Behavior of Guanosine Under Low Energy Collision-Induced Dissociation: H2O Adduct Formation and Gas-Phase Reactions in the Collision Cell

MALDI-TOF MS analysis of urinary nucleosides

Analysis of urinary nucleosides. I. Optimisation of high performance liquid chromatography/electrospray mass spectrometry

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Intriguing Mass Spectrometric Behavior of Guanosine Under Low Energy Collision-Induced Dissociation: H₂O Adduct Formation and Gas-Phase Reactions in the Collision Cell

Intriguing Mass Spectrometric Behavior of Guanosine Under Low Energy Collision-Induced Dissociation: H₂O Adduct Formation and Gas-Phase Reactions in the Collision Cell