A gene encoding deacetylase DA1 that is specific for N, N'-diacetylchitobiose was cloned using the shot-gun method with pUC118 and sequenced. The open reading frame encoded a protein of 427 amino acids including the signal peptide. The molecular mass of the mature enzyme estimated from the amino acid sequence data was 44.7 kDa, which is approximately similar to that, estimated by SDS-PAGE (48.0 kDa), of the purified enzyme reported previously. The N-terminal amino acid sequence deduced from the cloned deacetylase gene showed partial sequence homology with the Nod B protein from Rhizobium sp. (37% identity) and chitin deacetylase from Mucor rouxii (28%). It contained a domain, which showed homology with a chitin-binding domain of chitinase A from Bacillus circulans (39%).