Formate dehydrogenase from Candida boidinii(CboFDH) catalyses the oxidation of formate anion to carbon dioxide with concomitant reduction of NAD + to NADH. CboFDH is highly specific to NAD + and virtually fails to catalyze the reaction with NADP + . Based on structural informa-tion for CboFDH, the loop region betweenb-sheet 7 and a-helix 10 in the dinucleotide-binding fold was predicted as a principal determinant of coen-zyme specificity.