Dipeptide synthesis using acetylated trypsin derivative

A modified trypsin (AA-trypsin, acetylated with acetic acid N-hydroxysuccinimide ester) gave increased yields of Bzl-Arg-Leu-NH 2 dipeptide (90% versus 59% for native trypsin) when used in 95% acetonitrile. AA-Trypsin had decreased K m and increased k cat values for amide and ester substrates. k cat /K m also increased for each substrate upon modification. AA-Trypsin showed enhanced esterase activity in hydrophilic solvents compared with native enzyme.