DECREASED TYROSINE HYDROXYL ACIDITY THROUGH POLYALANYLATION

Publisher Website
Google Scholar
Abstract
It has been shown that polyalanylation of proteins and polypeptides leads to reduced dissociation constants for some of the tyrosine hydroxyl groups present in the original molecules. It is suggested that the formation of a hydrophobic bond between the polyalanyl peptide chain and the aromatic ring produces a less polar environment for the tyrosine hydroxyl groups, thus reducing its tendency to lose a proton and become and anion. It has been noted that differences in the extent of dissociation of tyrosine hydroxyl groups in polypeptides are correlated with anti-genicity, the polypeptide bearing less readily dissociable hydroxyl groups being nonantigenic. It is proposed that a simple molecule, N-carboxy N-alkylglycine anhydride, or a homologue thereof, might be used to reduce the antigenecity of proteins in vivo by forming groups which can give rise to hydrophobic bonds with aromatic rings.