DIRECT H-1-NMR EVIDENCE FOR CONVERSION OF BETA-D-CELLOBIOSE TO CELLOBIONOLACTONE BY CELLOBIOSE DEHYDROGENASE FROM PHANEROCHAETE-CHRYSOSPORIUM

The alpha- and beta-anomers of D-cellobiose were resolved by H-1 NMR s pectroscopy. Addition of cellobiose dehydrogenase purified from the wh ite-rot P. chrysosporium led to selective conversion of beta-D-cellobi ose. The product was identical to cellobionolactone as synthesized fro m Ca-cellobionate. overnight incubation of the product led to an alter ed NMR spectrum, which was also obtained by incubation of cellobionola ctone. The new spectrum matched that for Ca-cellobionate. The instabil ity of cellobionolactone explains the detection of cellobionic acid as product in earlier studies.