3-Mercaptopropionic acid

3-Mercaptopropionic acid (3-MPA) is an organosulfur compound with the formula HSCH2CH2CO2H. It is a bifunctional molecule, containing both carboxylic acid and thiol groups. It is a colorless oil. It is derived from the addition of hydrogen sulfide to acrylic acid.

Reactions and uses
It is competitive inhibitor of glutamate decarboxylase, and therefore acts as a convulsant. It has higher potency and faster onset of action compared to allylglycine.

It is used to prepare hydrophilic gold nanoparticles, exploiting the affinity of gold for sulfur ligands.

It is esterified with polyols to form thiol-based polymer cross-linking agents such as pentaerythritol-based pentaerythritol tetrakis(3-mercaptopropionate).