CHROMATOGRAPHIC BEHAVIOR OF CYCLODEXTRIN COMPLEXES OF NADH AND NADP

The retention behaviour of NADH and NADP on an ODS-C18 reversed-phase column was investigated by using a 0.05 M phosphate buffer (pH 6) containing α-, β- or γ-cyclodextrin (CD) as the mobile phase. Three reversible processes were assumed and the partition coefficients, k2, of inclusion complexes and their stability constants, K, were calculated. The value of k2 is clearly dependent on the molecular weight of the CD. It was established from the calculated values of K that NADH and NADP are liable to form more stable inclusion complexes with β-CD than α- and γ-CDs. NADP has a higher stability constant than NADH owing to the formation of hydrogen bonds between the phosphate moieties of NADP and the hydroxyl groups of CDs. © 1990.