L-(+)-2-Amino-4-thiophosphonobutyric acid (L-thioAP4), a new potent agonist of group III metabotropic glutamate receptors: increased distal acidity affords enhanced potency. Chelliah Selvam et al J. Med. Chem.
L-2-amino-4-phosphonobutyric acid (or L-AP4) is a drug used in scientific research, which acts as a group-selective agonist for the group III metabotropic glutamate receptors (mGluR4/6/7/8). It was the first ligand found to act as an agonist selective for this group of mGlu receptors,[1] but does not show selectivity between the different mGluR Group III subtypes. It is widely used in the study of this receptor family and their various functions.