Purification and characterization of aldehyde dehydrogenase with a broad substrate specificity originated from 2-phenylethanol-assimilating Brevibacterium sp. KU1309

Phenylacetaldehyde dehydrogenase (PADH) was purified and characterized from Brevibacterium sp. KU1309, which can grow on the medium containing 2-phenylethanol as the sole carbon source. This enzyme was a homotetrameric protein with a subunit of 61 kDa. The enzyme catalyzed the oxidation of aryl (benzaldehyde, phenylacetaldehyde, 3-phenylpropionaldehyde) and aliphatic (hexanal, octanal, decanal) aldehydes to the corresponding carboxylic acids using NAD⁺ as the electron acceptor. The PADH activity was enhanced by several divalent cationic ions such as Mg²⁺, Ca²⁺, and Mn²⁺. On the other hand, it was inhibited by SH reagents (Hg ²⁺, p-chloromercuribenzoate, iodoacetamide, and N-ethylmaleinimide). The substrate specificity of the enzyme is compared with those of various aldehyde dehydrogenases.