Synthesis of kyotorphin precursor from eutectic mixtures catalysed by alpha-chymotrypsin

The kyotorphin precursor, N-carbobenzoxyl-L-tyrosine-L-arginine amide (N-CB Z-L-Tyr-L-ArgNH(2)), was synthesized from N-CBZ-L-tyrosine ethyl ester (N-C BZ-L-TyrOEt) and L-arginine amide (l-ArgNH(2)) by using alpha -chymotrypsin . Eutectic mixtures were formed by mixing the substrates in the presence of water and/or organic solvents as adjuvants. The eutectic temperature was o btained with a 0.45 l-ArgNH(2) mole fraction. It was lowered to 23 degreesC by addition of 10% (v/w) water and 5% (v/w) dimethyl formamide, thus maint aining homogeneous liquid states at the reaction temperature of 30 degreesC . After 9 h the solutions became solidified and no further reaction took pl ace. Approximately 90% (mol/mol) conversion was achieved from the substrate mixtures with substrate contents responsible for more than 80% (w/w) of th e total mixture.