Determination of 7-methylguanine, N2,N2-dimethylguanosine, and pseudouridine in ultrafiltrated serum of healthy adults by high-performance liquid chromatography.
7-Methylguanine (m7Gua), N2,N2-dimethylguanosine (m2(2)Guo), and pseudouridine (psi) are degradation products from RNA turnover and can be used as markers for the whole-body turnover of mRNA-cap, tRNA, and rRNA (in healthy individuals, urinary excretion of these catabolites follows a regular pattern; the relative molar ratio of psi:m7Gua:m2(2)Guo is approximately 100:19:6). HPLC methods were developed to measure serum concentrations of these RNA catabolites after deproteinization of the samples by ultrafiltration through microcollodion bags with a nominal exclusion Mr of 12,400. For healthy adults the following values (mean +/- SD) were found: psi, 2760 +/- 460 nmol/liter (n = 10); m7Gua, 129.7 +/- 24.0 nmol/liter (n = 13); m2(2)Guo, 31.0 +/- 3.7 nmol/liter (n = 9). The relative molar ratio of these substances in serum derived from our data is approximately 100:4.7:1.1. 7-Methylguanosine (m7Guo) added to serum is to a large extent converted to the corresponding free base, m7Gua, the form which is excreted in urine.
D000328:Adult; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006147:Guanine / Q000031:analogs & derivatives* / Q000097:blood; D006151:Guanosine / Q000031:analogs & derivatives* / Q000097:blood; D006801:Humans; D011560:Pseudouridine / Q000097:blood*; D012313:RNA / Q000378:metabolism; D012016:Reference Values; D013056:Spectrophotometry, Ultraviolet; D014462:Ultrafiltration; D014529:Uridine / Q000031:analogs & derivatives*
D006151:Guanosine; D011560:Pseudouridine; C008940:N(2),N(2)-dimethylguanosine; D006147:Guanine; D012313:RNA; C008450:7-methylguanine; D014529:Uridine