7-Methylguanosine is a methylated form of the purine nucleoside guanosine . It is an RNA modification that is present in the 5’-terminal cap of mRNA, where it promotes translation, as well as in tRNA, where it stabilizes the tRNA structure.1,2 7-Methylguanosine has been used as a substrate to measure the activity of purine nucleoside phosphorylase (PNP).3 Urinary 7-methylguanosine levels are decreased in patients with prostate cancer.1
1.Fernández-Peralbo, M.A., Gómez-Gómez, E., Calderón-Santiago, M., et al.Prostate cancer patients-negative biopsy controls discrimination by untargeted metabolomics analysis of urine by LC-QTOF: Upstream information on other omicsSci. Rep.638243(2016) 2.Tomikawa, C.7-Methylguanosine modifications in transfer RNA (tRNA)Int. J. Mol. Sci.19(12)4080(2018) 3.Stachelska-Wierzchowska, A., and Wierzchowski, J.Non-typical nucleoside analogs as fluorescent and fluorogenic indicators of purine-nucleoside phosphorylase activity in biological samplesAnal. Chim. Acta1139119-128(2020)