MALDI-TOF MS analysis of urinary nucleosides.

Area of Science:

• Biochemistry
• Analytical Chemistry
• Oncology

Background:

• RNA turnover is altered in cancer patients.
• Modified nucleosides, particularly methylated ones, are elevated in cancer patient urine.
• These nucleosides are potential biomarkers for cancer detection.

Purpose of the Study:

• To structurally elucidate known and unknown nucleosides in urine from cancer patients.
• To evaluate the utility of MALDI-TOF MS and MALDI-PSD for nucleoside analysis.
• To develop an improved method for detecting low molecular weight compounds using MALDI-TOF MS.

Main Methods:

• Prepurification of urinary nucleosides using affinity chromatography.
• Separation of nucleosides by semipreparative high-performance liquid chromatography (HPLC).
• Analysis of separated fractions using MALDI-TOF MS and PSD-MALDI with internal/external calibration.

Main Results:

• Identified several known urinary nucleosides previously characterized by HPLC retention times and UV spectra.
• Observed and characterized eight additional nucleosides.
• Demonstrated the effectiveness of the combined HPLC-MALDI-TOF/PSD-MS approach for nucleoside identification.

Conclusions:

• MALDI-TOF MS and PSD-MALDI coupled with semipreparative HPLC are powerful tools for assigning nucleosides in urine.
• The high mass accuracy of this mass spectrometry method facilitates the identification of unknown compounds.
• This approach shows promise for advancing cancer biomarker discovery through urinary nucleoside analysis.