Induction and regulation of D-xylose catabolizing enzymes in Fusarium oxysporum.

In Fusarium oxysporum DSM 841, the requirement of oxygen was found to be associated with the induction of key D-xylose catabolizing enzymes. NADPH-linked D-xylose reductase and NAD-linked xylitol dehydrogenase. Both enzymes were detected in cell free extracts of F. oxysporum grown in the medium containing D-xylose, L-arabinose and D-galactose as substrate. D-xylose, L-arabinose and D-galactose were also found to be substrates for NADPH-linked activities. However, unlike xylitol, neither L-arabitol nor galactitol supported the NAD-linked reactions, suggesting the diversion of metabolic pathways of L-arabinose and D-galactose from that of D-xylose following formation of pentitol.