(phenol saturated with 50 mM sodium acetate, pH 5.8) and alcohol precipitation
20 (link). Nucleosides were prepared as
described in 61 (link) by hydrolyzing bulk tRNA
with 10 units of Nuclease P1 (Sigma) overnight at 37°C, with the addition of
0.01 units of phosphodiesterase I (Sigma) and 3 µL E. colialkaline phosphatase (Sigma). The hydrolyzed nucleosides were further purified
by filtering through a 5 kD MWCO filter (Millipore) (to remove enzymes), dried
in a CentriVap Concentrator, and suspended in 20 µL of water prior to analysis
by HPLC or LC-MS/MS.