O-Phospho-D-serine is a phosphorylated form of D-serine, a natural amino acid made from L-serine by serine racemase in the mammalian central nervous system. It can be dephosphorylated by phosphoserine phosphatase, like its isomer O-phospho-L-serine (L-SOP; ). Unlike L-SOP, O-phospho-D-serine is a weak agonist of the metabotropic glutamate receptor mGluR4 (IC50 = 1,260 μM vs. 4 μM for L-SOP) and poorly blocks phosphatidylserine receptor-mediated phagocytosis.
