a 2-oxocarboxylate + H(+) = an aldehyde + CO2 Binds 1 metal ion per subunit. Binds 1 thiamine pyrophosphate per subunit. Homotetramer. Expressed at low levels in roots, shoots, flowers, siliques and seeds. By abscisic acid (ABA), salt, osmotic stress, wounding and paraquat. Not induced by anoxia. Belongs to the TPP enzyme family. Sequencing errors.