label: 3,3'-bipyridine-2,2',5,5',6,6'-hexol + NAD(+) => (E)-2,2',5,5'-tetrahydroxy-6H,6'H-(3,3'-bipyridinylidene)-6,6'-dione + NADH + 3 H(+)
label_lc: 3,3'-bipyridine-2,2',5,5',6,6'-hexol + nad(+) => (e)-2,2',5,5'-tetrahydroxy-6h,6'h-(3,3'-bipyridinylidene)-6,6'-dione + nadh + 3 h(+)