Relative Significance of Electrostatic‐ and Hydrophobic‐Induced p<i>K</i>_a Shifts in a Model Protein: The Aspartic Acid Residue

Abstract

Unusual p K a values for amino acids in the active sites of proteins play a large role in their function. A new explanation for these p K a shifts, which considers not electrostatic but mainly hydrophobic interactions as the cause, is presented here. This is substantiated by the correlation between the titrimetrically determined p K a values of a family of polypentapeptides containing aspartic acid and the aspartic acid content in the polypeptide.