4-N-trimethylaminobutyraldehyde dehydrogenase: purification and characterization of an enzyme from Pseudomonas sp. 13CM.

4-N-trimethylaminobutyraldehyde dehydrogenase from Pseudomonas sp. 13CM was purified 14-fold to apparent homogeneity by hydrophobic chromatography on a Phenyl-Toyopearl, and affinity chromatography was done on a 5'-AMP Sepharose4B in the presence of dithiothreitol. The enzyme was found to be a trimer with identical 55 kDa subunits. The isoeletric point was found to be 5.5. The optimum temperature and pH were 40 degrees C and pH 10.0. The purified enzyme was further characterized with respect to substrate specificity, kinetic parameters, and analog inhibition. The K(m) values for 4-N-trimethylaminobutyraldehyde, 4-dimethylaminobutyraldehyde, and NAD(+) were 7.4, 51, and 125 microM respectively. The enzyme was inhibited by SH reagents, and by heavy metal ions.