Kinetically controlled enzymatic synthesis of dipeptide precursor of l -alanyl- l -glutamine

摘要

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 donorucleophile 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 Ka mapp and the apparent maximum reaction rate ra maxapp were calculated as 1.71 mol/L and 6.09 mmol/(L Min), respectively.