A gene encoding an ether-bond-cleaving enzyme, diglycolic acid dehydrogenase (DGADH) from polyethylene glycol-utilizing Pseudonocardia sp. strain K1, was cloned and expressed in Escherichia coli. The deduced amino acid sequence had a high homolog with superoxide dismutases (SODs) from various bacteria. The recombinant protein showed the same activities as those of DGADH front Pseudonocardia sp. strain K1, namely. SOD activity and ether-bond-cleaving activity.