Description
Selenophosphate, which is the active donor of selenium in selenocysteine (Sec) biosynthesis is synthesized from selenite and ATP by an enzyme designated as selenophosphate synthetase (SPS).There are two isoforms of SPS in higher eukaryotes,SPS1 and SPS2. Initially, both SPS1 and SPS2 were thought to be involved in selenophosphate synthesis. However, it was subsequently shown that only SPS2 catalyzes selenophosphate synthesis. Although SPS1 is an essential gene in Drosophila, its function has not been determined.