Continuous production of 3-fluoro-L-alanine with alanine dehydrogenase.
Alanine dehydrogenase catalyzed the conversion of 3-fluoropyruvate into 3-fluoro-L-alanine in the presence of NADH and ammonia. The optimum pH of the reaction was 7.8. The K(m) values of the enzyme for 3-fluoropyruvate, polyethylene glycol-bound NADH, and ammonia were 2.94, 0.56, and 105mM, respectively. 3-Fluoro-L-alanine was selectively and continuously produced from 3-fluoropyruvate and ammonium formate in an enzyme membrane reactor by the multienzyme reaction system of alanine dehydrogenase and formate dehydrogenase with a simultaneous coenzyme regeneration. The average conversion and the space-time yield were 73% and 75 g/L day, respectively, with operation of the reactor for 4 days. Alanine dehydrogenase and formate dehydrogenase consumed were 11, 370 and 22, 950 units/kg 3-fluoro-L-alanine, respectively. The cycle number was 3150 mol/mol NAD.
Ohshima
T
T
Department of Chemistry, Kyoto University of Education, Fushimi-ku Kyoto 612, Japan.
Wandrey
C
C
Conrad
D
D