2.9.1.2	L-phosphoseryl-tRNASec + selenophosphate	-	Trypanosoma brucei	L-selenocysteinyl-tRNASec + phosphate	-	?	398919	
2.9.1.2	L-phosphoseryl-tRNASec + selenophosphate	selenocysteine is the only genetically encoded amino acid in humans whose biosynthesis occurs on its cognate transfer RNA (tRNA). O-Phosphoseryl-tRNA:selenocysteinyl-tRNA synthase catalyzes the final step of selenocysteine formation by a tRNA-dependent mechanism	Homo sapiens	L-selenocysteinyl-tRNASec + phosphate	-	?	398919	
2.9.1.2	additional information	bacterial SepCysS charges bacterial tRNACys species with cysteine in vitro. Sep-tRNACys is converted by Sep-tRNA:Cys-tRNA synthase (SepCysS) to Cys-tRNACys	Bacteria	?	-	-	89	
2.9.1.2	additional information	Sep-tRNACys is converted by Sep-tRNA:Cys-tRNA synthase (SepCysS) to Cys-tRNACys	Archaea	?	-	-	89	
2.9.1.2	additional information	SepSecS binds unacylated tRNASec equally well as Sep-tRNASec 1	Homo sapiens	?	-	-	89	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate	-	Trypanosoma brucei	L-selenocysteinyl-tRNASec + phosphate	-	?	398974	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate	-	Homo sapiens	L-selenocysteinyl-tRNASec + phosphate	-	?	398974	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate	-	Methanococcus maripaludis	L-selenocysteinyl-tRNASec + phosphate	-	?	398974	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate	-	Methanocaldococcus jannaschii	L-selenocysteinyl-tRNASec + phosphate	-	?	398974	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate	L-phosphoseryl-tRNA is the crucial precursor for L-selenocysteinyl-tRNA formation in archaea and eukarya. Selenocysteine formation is achieved by a two-step process: O-phosphoseryl-tRNASec kinase (PSTK) phosphorylates the endogenous Ser-tRNASec to O-phosphoseryl-tRNASec, and then this misacylated amino acid-tRNA species is converted to L-selenocysteinyl-tRNASec by Sep-tRNA:Sec-tRNA synthase (SepSecS)	Methanococcus maripaludis	L-selenocysteinyl-tRNASec + phosphate	-	?	398974	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate	L-phosphoseryl-tRNA is the crucial precursor for L-selenocysteinyl-tRNA formation in archaea and eukarya. Selenocysteine formation is achieved by a two-step process: O-phosphoseryl-tRNASec kinase (PSTK) phosphorylates the endogenous Ser-tRNASec to O-phosphoseryl-tRNASec, and then this misacylated amino acid-tRNA species is converted to L-selenocysteinyl-tRNASec by Sep-tRNA:Sec-tRNA synthase (SepSecS)	Methanocaldococcus jannaschii	L-selenocysteinyl-tRNASec + phosphate	-	?	398974	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate	L-phosphoseryl-tRNA is the crucial precursor for L-selenocysteinyl-tRNA formation in archaea and eukarya. Selenocysteine formation is achieved by a two-step process: O-phosphoseryl-tRNASec kinase phosphorylates the endogenous L-seryl-tRNASec to O-phospho-L-seryl-tRNASec, and then this misacylated amino acid-tRNA species is converted to L-selenocysteinyl-tRNASec by Sep-tRNA:Sec-tRNA synthase	Homo sapiens	L-selenocysteinyl-tRNASec + phosphate	-	?	398974	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate	null mutants of SepSecS abolish selenoprotein synthesis, demonstrating the essentiality of the enzyme for the formation of L-selenocysteinyl-tRNASec. Growth of the knockout strain is not impaired. Thus, unlike mammals, trypanosomes do not require selenoproteins for viability	Trypanosoma brucei	L-selenocysteinyl-tRNASec + phosphate	-	?	398974	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate	SepSecS is a key enzyme required for the synthesis of the trypanosomal selenoproteins. The enzyme does not affect growth of bloodstream forms of Trypanosoma brucei	Trypanosoma brucei	L-selenocysteinyl-tRNASec + phosphate	-	?	398974	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate	the micronutrient selenium is present in proteins as selenocysteine. In eukaryotes and archaea, selenocysteine is formed in a tRNA-dependent conversion of O-phosphoserine by O-phosphoseryltRNA:selenocysteinyl-tRNA synthase	Methanococcus maripaludis	L-selenocysteinyl-tRNASec + phosphate	-	?	398974	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate	proposed pyridoxal 5'-phosphate mechanism of L-phosphoseryl-tRNA to L-selenocysteinyl-tRNA conversion: the reaction begins by the covalently attached O-phospho-L-serine being brought into the proximity of the Schiff base when L-phosphoseryl-tRNASec binds to the enzyme. The amino group of O-phospho-L-serine can then attack the Schiff base formed between Lys284 and pyridoxal 5'-phosphate, which yields an external aldimine. The reoriented side chain of Lys284 abstracts the Calpha proton from O-phospho-L-serine, and the electron delocalization by the pyridine ring assists in rapid beta-elimination of the phosphate group, which produces an intermediate dehydroalanyl-tRNASec. After phosphate dissociation and binding of selenophosphate, the concomitant attack of water on the selenophosphate group and of the nucleophilic selenium onto the highly reactive dehydroalanyl moiety yield an oxidized form of L-phosphoseryl-tRNASec. The protonated Lys284, returns the proton to the Calpha carbon and then attacks pyridoxal 5'-phosphate to form an internal aldimine. Finally, Sec-tRNASec is released from the active site	Homo sapiens	L-selenocysteinyl-tRNASec + phosphate	-	?	398974	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate + H2O	-	Leishmania donovani	L-selenocysteinyl-tRNASec + phosphate	-	?	436534	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate + H2O	-	Leishmania donovani Bob	L-selenocysteinyl-tRNASec + phosphate	-	?	436534	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate + H2O	-	Bacteria	L-selenocysteinyl-tRNASec + 2 phosphate	-	?	458668	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate + H2O	-	Archaea	L-selenocysteinyl-tRNASec + 2 phosphate	-	?	458668	
2.9.1.2	O-phospho-L-seryl-tRNASec + selenophosphate + H2O	-	Homo sapiens	L-selenocysteinyl-tRNASec + 2 phosphate	-	?	458668