In Escherichia coli and Salmonella typhimurium it has been shown that selenophosphate serves as the selenium donor for the conversion of seryl- tRNA to selenocysteyl-tRNA and for the synthesis of 2-selenouridine, a modified nucleoside present in tRNAs. Although selenocysteyl-tRNA also is formed in eukaryotes and is used for the specific insertion of selenocysteine into proteins, the precise mechanism of its biosynthesis from seryl-tRNA in these systems is not known. Because selenophosphate is extremely oxygen labile and difficult to identify in biological systems, we used an immunological approach to detect the possible presence of selenophosphate synthetase in mammalian tissues. With antibodies elicited to E. coli selenophosphate synthetase the enzyme was detected in extracts of rat brain, liver, kidney, and lung by immunoblotting. Especially high levels were detected in Methanococcus vannielii, a member of the domain Archeae, and the enzyme was partially purified from this source. It seems likely that the use of selenophosphate as a selenium donor is widespread in biological systems.
|Number of pages||4|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - 1995 Aug 15|
- mammalian selenophosphate synthetase
ASJC Scopus subject areas