Biochemistry

NAD contains two residues of nitrogenous bases, the remains of two riboses and two phosphoric acids. One nitrogenous base is adenine, the second is nicotinic acid amide, which is characterized by the function of vitamin PP (antipellagric). From the names of nitrogenous bases, the abbreviation NAD arose. The hydrogen acceptor in NAD and NADP is nicotinamide in both oxidized and reduced forms. In oxidized form, this compound contains pentavalent nitrogen in the ring. After reduction, one hydrogen atom joins the carbon, as a result of which its double bond with the neighboring atom breaks. The electron of the second hydrogen atom extinguishes the charge of pentavalent nitrogen, and it is converted to trivalent. The addition of an electron and the reduction of valency is a restoration process. The remaining proton goes into the medium. OH OH Nicotinamide adenine dinucleotide (NAD) C- — CONH, Nicotinamide adenine dinucleotide phosphate (NADP) C — CONH, 106