Purification and properties of carnitine dehydrogenase from Pseudomonas putida

Carnitine dehydrogenase (carnitine:NAD+ oxidoreductase, EC 1.1.1.108) from Pseudomonas putida IFP 206 catalyzes the oxidation of L-carnitine to 3-dehydrocarnitine. The enzyme was purified 72-fold to homogeneity as judged by polyacrylamide gel electrophoresis. The molecular mass of this enzyme is 62 kDa and consists of two identical subunits. The isoelectric point was found to be 4.7. the carnitine dehydrogenase is specific for L-carnitine and NAD+. The optimum pH for enzymatic activity in the oxidation reaction was found to be 9.0 and 7.0 in the reduction reaction. The optimal temperature is 30 degrees C. The Km values for substrates were determined.