Enzymatic synthesis of a vitamin B6 precursor

Abstract

3-Cyano-4-(ethoxymethyl)-6-methyl-2-pyridone, an important precursor in the synthesis of vitamin B6, is obtained in the addition reaction between 2-cyanoacetamide and 1-ethoxy-2,4-pentanedione catalyzed by lipase from Candida rugosa (triacylglycerol acylhydrolases, EC 3.1.1.3). This work shows new experimental data and mathematical modeling of the lipase-catalyzed synthesis of 3-cyano-4-(ethoxymethyl)-6-methyl-2-pyridone. Kinetic measurements were performed at 50 °C with an enzyme concentration of 1.2 % w/v. The experimental results were fitted with two kinetic models: the ordered bi-ter and ping-pong bi-ter model, and the initial rates of the reaction were found to correlate best with the ping-pong bi-ter mechanism with inhibition by 2-cyanoacetamide. The obtained specificity constants indicated that lipase from C. rugosa had a higher affinity towards 1-ethoxy-2,4-pentanedione compared to 2-cyanoacetamide.