The enzyme catalyzing the conversion of N-alpha-benzyloxycarbonyl-L-aminoadipic-delta-semialdehyde (N-alpha-Z-L-AASA) to N-alpha-benzyloxycarbonyl-L-aminoadipic acid (N-alpha-Z-L-AAA) in Aspergillus niger AKU 3302 was identified, and its characteristics were revealed. This reaction was catalyzed by an oxidase with a molecular mass of 215 kDa and pI of 4.1. The enzyme exhibited oxidase activity on N-alpha-Z-L-AASA but not on short-chain aliphatic aldehydes, aromatic aldehydes or alcohols. The apparent K-m value for N-alpha-Z-L-AASA was estimated to be 7.0 mM. Thus, N-alpha-Z-L-lysine was converted to N-alpha-Z-L-AAA via N-alpha-Z-L-AASA by a combination of an amine oxidase with broad substrate specificity and an aldehyde oxidase specific to N-alpha-Z-L-AASA in A. niger AKU 3302.