Proline racemase (null)

Proline racemase is an enzyme that catalyzes the interconversion of L-proline and D-proline. It is found in bacteria and certain protozoan parasites, like Trypanosoma cruzi, but is absent in mammals. The enzyme functions via a pyridoxal phosphate-independent, two-base mechanism, involving two active-site cysteine residues that operate as general acids/bases. In T. cruzi, the secreted form of proline racemase acts as a B-cell mitogen and plays a role in immune evasion during Chagas disease. Structurally, it is a homodimer, with each monomer hosting an active-site capable of catalysis. Transition state analogues, particularly pyrrole-2-carboxylic acid, inhibit the enzyme by mimicking the substrate’s transition state, binding to the catalytic center and blocking function. The absence of proline racemase in mammals and its essential role in pathogenic organisms make it an attractive target for selective drug development.

Other names

Proline amino acid racemasePRACL-proline racemaseD-proline racemase

Inhibitors block enzyme-mediated racemization of proline by covalently or non-covalently interfering with active-site cysteine residues, preventing conversion of L- to D-proline or vice versa