A SHORT-CHAIN DEHYDROGENASE GENE FROM PICHIA-STIPITIS HAVING D-ARABINITOL DEHYDROGENASE-ACTIVITY

An NAD(+)-dependent D-arabinitol dehydrogenase (polyol dehydrogenase) gene was isolated from Pichia stipitis CBS 6054 and cloned in Saccharo myces cerevisiae. The gene was isolated by screening of a lambda-cDNA library with a zymogram technique. D-Arabinitol, xylitol, D-glucitol a nd galactitol are substrates for the recominant protein. With D-arabin itol as substrate the reaction product is D-ribulose. The molecular we ight of the native tetramer enzyme is 110 000 Da and the monomer is 30 000 Da. The amino acid sequence is homologous to the short-chain dehy drogenase family. It is 85.5% identical to a D-arabinitol dehydrogenas e from Candida albicans. The gene in P. stipitis was induced by D-arab initol and P. stipitis was able to grow on D-arabinitol. The physiolog ical role of D-arabinitol metabolism is discussed.