Kinetically controlled enzymatic synthesis of dipeptide precursor of l ‐alanyl– l ‐glutamine

An important nutritional dipeptide precursor, benzoyloxycarbonyl protected l ‐alanyl– l ‐glutamine (Z–Ala–Gln), was successfully prepared through a kinetically controlled enzymatic peptide synthesis method. A commercially available and low‐cost protease (papain) was used as biocatalyst with Z–Ala–OMe and Gln as acyl donor and nucleophile, respectively. The dipeptide yield was 35.5% under the optimized reaction conditions: 35°C, pH 9.5, and the ratio of acyl donor/nucleophile is 1:10. Based on the reaction mechanism and experimental data, the kinetic model was established, which was in accordance with the Michaelis–Menten equation, and the apparent Michaelis constant K   m appand the apparent maximum reaction rate r   max appwere calculated as 1.71 mol/L and 6.09 mmol/(L Min), respectively.