Direct 1H NMR evidence for conversion of β- d-cellobiose to cellobionolactone by cellobiose dehydrogenase from Phanerochaete chrysosporium

The α- and β-anomers of d-cellobiose were resolved by 1H NMR spectroscopy. Addition of cellobiose dehydrogenase purified from the white-rot P. chrysosporiumled to selective conversion of β- d-cellobiose. The product was identical to cellobionolactone as synthesized from Ca-cellobionate. Overnight incubation of the product led to an altered NMR spectrum, which was also obtained by incubation of cellobionolactone. The new spectrum matched that for Ca-cellobionate. The instability of cellobionolactone explains the detection of cellobionic acid as product in earlier studies.