Role of catalytic residues in the formation of a tetrahedral adduct in the acylation reaction of bovine β-trypsin: A molecular orbital study☆

摘要: In the acylation reaction of serine proteases effect amino acid residues on geometrical change catalytic site from Michaelis to tetrahedral state was studied by using ab initio molecular orbital calculations. Amino in and peptide substrate were calculated as a quantum mechanical region, all other calcium ion included calculation electrostatic effects. The effects Asp102, Asp194, N-terminus oxyanion binding are large. directly stabilizes substrate. Asp102 enzyme intermediate, interacting with protonated His57 residue. order elucidate roles site, energy decomposition analyses done for intermolecular interactions. contribution decrease is due effect. energies proton shuttle Ser195 Oγ leaving group amide ester models.