alpha-chymotrypsin and methyl-acetate

Mechanistic steps of the catalytic hydrolysis of methylacetate by alpha-chymotrypsin have been studied with the inhomogeneous selfconsistent reaction field theory of protein core effects. Protein-substrate interactions were optimized at each step of the reaction path by using the REFINE program. The state of charge of the acid and basic side chains together with the amino terminal group have been used to mimic pH effects. The experimental facts concerning the catalytic activity are fairly well reproduced in our simulations. In particular, the trends in activation barrier as a function of pH are good, although the actual energetic barriers are much too large.

Topics: Acetates; Amino Acid Sequence; Binding Sites; Chemical Phenomena; Chemistry; Chymotrypsin; Hydrogen-Ion Concentration; Hydrolysis; Models, Biological; Software; Thermodynamics