Mathematical determination of kinetic parameters for assessing the effect of the organic solvent on the selectivity of peptide synthesis with immobilized α-chymotrypsin

The synthesis of the dipeptide N-benzoyl-l-tyrosine-l-argininamide (BTAA) was conducted under kinetic control with N-benzoyl-l-tyrosine ethyl ester as acyl donor and argininamide as nucleophile using immobilized α-chymotrypsin as catalyst. Using a mathematical procedure, the kinetic constants corresponding to the proposed mechanism of peptide synthesis were determined in three different cosolvent media, namely, ethanol, diglyme and acetonitrile. These constants were used for evaluating the selectivity of glyoxyl-agarose immobilized α-chymotrypsin in the synthesis of BTAA by determining the ratios of synthesis to hydrolysis rates. •Immobilized α-chymotrypsin was used for synthesizing a kyotorphin precursor.•Methodology was validated for determining the kinetic parameters of the reaction.•Selectivity of the reaction was determined from synthesis and hydrolysis rates.•Ethanol, diglyme and acetonitrile were used as reaction media.•Selectivity toward peptide synthesis was highest in diglyme.