Polyethylene Glycol Modified Trypsin Kinetics in Buffer and in Benzene: Dipeptide Synthesis

Abstract

Trypsin, on chemical modification with 2-[(s`-monomethoxy) polyethyleneglycol]-4,6-dichloro-s-triazine, is soluble in benzene. In buffer, this modification increased the amidolytic and esterolytic molecular activity kcat relative to the native enzyme and decreased strongly the Michaelis constant Km of Nα-benzoyl-L-arginine-p-nitroanilide (Bz-L-Arg-NH-Np), whilst that of Nα-benzoyl-L-arginine ethyl ester (Bz-L-ArgOEt) did not change. The modified enzyme catalyzed the aminolysis of the anilide in benzene with trace amounts of water. Syntheses of dipeptides were enzymatically performed with high yields using Narbenzoyl-L-arginine ethyl ester or Nα-benzoyl-L-lysine methyl ester (Bz-L-LysOMe) as acyl-group donors, and L-leucinamide (L-LeuNH2) as an acceptor nucleophile.