O-Methylsterigmatocystin
O-Phospho-L-serine is the immediate precursor to L-cystein in the serine synthesis pathway, and an agonist at the group III mGluR receptors (mGluR4, mGluR6, mGluR7, and mGluR8); O-Phospho-L-serine also acts as a weak antagonist for mGluR1 and a potent antagonist for mGluR2[1].