Can the combination of electrochemical regeneration of NAD+, selectivity of L‐α‐amino‐acid dehydrogenase, and reductive amination of α‐keto‐acid be applied to the inversion of configuration of a L‐α‐amino‐acid?

摘要: The inversion of configuration L-alanine can be carried out by combining its selective oxidation in the presence NAD+ and dehydrogenase, electrochemical regeneration at a carbon felt anode, reductive amination pyruvate, i.e., reduction imino derivative mercury cathode, reaction mixture being buffered with concentrated ammonium/ammonia (1.28M / 1.28M). dehydrogenase exhibits astonishing activity stability under such extreme conditions pH ionic strength. The main drawback process is slowness. At best, complete 10 mM solution requires 140 h. A careful detailed quantitative analysis each key steps involved shows that enzyme catalyzed so thermodynamically uphill it driven efficiently to completion only when both coenzyme pyruvate are very effective. first condition easily fulfilled. Under best conditions, rate chemical producing imine which controls whole kinetically. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 64: 101–107, 1999.