Tartaric Acid Metabolism

Tartrate dehydrogenase from Pseudomonas putida has been purified and crystallized. The enzyme catalyzes the reversible, DPN-linked oxidation of mesotartrate and of l(+)-tartrate to oxaloglycolate; l(-)- and d(+)-malate are inactive as either substrates or inhibitors. The enzyme requires manganous ions and one of several monovalent cations for activity. Both qualitative and quantitative differences are found in the requirement for monovalent cation, depending on whether meso- or l(+)-tartrate serves as substrate. The active enzyme has a molecular weight of 145,000 and appears to be composed of four subunits, each of which has a molecular weight of approximately 36,800.