<p>The invention concerns the enzymatic synthesis of stable analogues of nicotinamide adenine dinucleotide NAD/NADH and nicotinamide adenine dinucleotide phosphate NADP/NADPH, the so-called "carba-NADs", i.e. analogues of NAD/NADH or NADP/NADPH, respectively, comprising a carbacyclic sugar instead of ribose.</p>