Isolation and partial characterization of selenium-containing tRNA from germinating barley

Selenium-containing tRNA was discovered in germinating barley for the first time with the Se-75 isotopic tracer technique; therefore, this technique w as used to study the effect of different concentrations of selenium and sul fur in the medium on the content of selenium-containing tRNA in germinating barley. Se-containing tRNAs and its hydrolysates were isolated, purified, and characterized by means of column chromatography, ion-exchange chromatog raphy, high-performance liquid chromatography, and the ultraviolet-visible spectrum. The results show that the amount of selenium in tRNA is almost un affected by the sulfuric content in the medium, and the pathway for seleniu m and sulfur to enter tRNA might not be exactly the same. Selenium exists w ithin tRNA in the form of 5-methylamine methyl-2-selenouridine, just as it does within a microorganism tRNA.