STEREOSELECTIVE HYDRIDE UPTAKE IN MODELSYSTEMS RELATED TO THE REDOX-COUPLE NAD+/NADH

Article abstract of DOI:10.1016/S0040-4020(01)87502-5

The present work deals with the mechanistic investigations of the hydride transfer reactions concerning the redox couple NAD⁺/NADH.Based on the theoretical and experimental investigations of NAD(H) model compounds as 3-carbamoyl pyridinium cations (3-carbamoyl-1,4-dihydropyridine) it was found that the out-of-plane rotation of the carboyl function controls the stereo- and regiospecificity of the introduced hydride anion.It was found that the hydride anion transfered in the reaction, is always syn-positioned with respect to the carbonyl group.The unique stereoselectivity exhibits a strong coherence with the recent crystallographic 3D-data for the ternary complex of NAD bonded horse liver alcohol dehydrogenase.The results show that the amide group is 30 deg out of the plane with the carbonyl directed toward the A side.There are observations that the absolute configuration of the introduced chirality in the 3-carbamoyl pyridinium cations selects between the hydride uptake corresponding with the enzymatic A or B specificity.