4-N-Trimethylaminobutyraldehyde Dehydrogenase: Purification and Characterization of an Enzyme from Pseudomonas sp. 13CM

Abstract

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 °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 μM respectively. The enzyme was inhibited by SH reagents, and by heavy metal ions.