Cloning and expression of NAD+-dependent L-arabinitol 4-dehydrogenase gene (ladA) of Aspergillus oryzae

A gene of Aspergillus oryzae, ladA, which encodes L-arabinitol 4-dehydrogenase (EC 1.1.1.12), and its cDNA were cloned in Escherichia coli. The gene consisted of a 1209-bp coding region, interrupted by a 59-bp intron, which encoded a 382-amino-acid polypeptide (40,812 Da). The protein showed 67% identity to a well-studied L-arabinitol 4-dehydrogenase (Lad1) of Hypocrea jecorina. The cell-free extract of E. coli, which expressed ladA cDNA, showed L-arabinitol dehydrogenase activity with NAD+. It was also reactive for ribitol and xylitol.