B6db activities : 2_9_1

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	2.9.1.1
Description	L-seryl-tRNA(Sec) selenium transferase.
Alternative names	Selenocysteine synthase. L-selenocysteinyl-tRNA(Sel) synthase. L-selenocysteinyl-tRNA(Sec) synthase. Cysteinyl-tRNA(Sel)-selenium transferase. Cysteinyl-tRNA(Sec)-selenium transferase.
Catalyzed reaction	L-seryl-tRNA(Sec) + selenophosphate = L-selenocysteinyl-tRNA(Sec) + H(2)O + phosphate.
Cofactor	Pyridoxal-phosphate.
Comments	-!- Recognizes specifically tRNA(Sec)-species. Binding of tRNA(Sec) also occurs in the absence of the seryl group. -!- 2-Aminoacryloyl-tRNA, bound to the enzyme as an imine with the pyridoxal phosphate, is an intermediate in the reaction. -!- Since the selenium atom replaces oxygen in serine, the product may also be referred to as L-selenoseryl-tRNA(Sel). -!- The abbreviation Sel has also been used for selenocysteine but Sec is preferred.
	This specific activity occurs apparently only in bacteria; in archaea and eukaryotes, the L-selenocysteinyl-tRNA species is synthesized from O-phosphoseryl-tRNA(Ser) by Sec synthase (L-phosphoseryl-tRNA(Ser):selenophosphate seleniumtransferase).
Organisms	-Bacteria
Family	2.9.1.1 (28)

Links	Enzyme (activities) 2.9.1.1 BRENDA (activities) 2.9.1.1 KEGG (pathways) 2.9.1.1 PLPMDB (PLP mutants) 2.9.1.1

References	Gursinsky, T.; Jager, J.; Andreesen, J. R.; Sohling, B. (2000) A selDABC cluster for selenocysteine incorporation in Eubacterium acidaminophilum Arch Microbiol 174 200-12.. Tormay, P.; Wilting, R.; Lottspeich, F.; Mehta, P. K.; Christen, P.; Bock, A. (1998) Bacterial selenocysteine synthase--structural and functional properties Eur J Biochem 254 655-61.. Forchhammer, K.; Leinfelder, W.; Boesmiller, K.; Veprek, B.; Bock, A. (1991) Selenocysteine synthase from Escherichia coli. Nucleotide sequence of the gene (selA) and purification of the protein J Biol Chem 266 6318-23.. Articles on 2.9.1.1

last changed	2007/12/19 16:20

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