D-cellobiono-1,5-lactone + AH2 => D-cellobiose + A
d-cellobiono-1,5-lactone + ah2 => d-cellobiose + a
D-cellobiono-1,5-lactone + AH2 => D-cellobiose + A
d-cellobiono-1,5-lactone + ah2 => d-cellobiose + a