Liberation of Carboxyl Groups on Conversion of Ovalbumin tos-Ovalbumin

Titration curves of ovalbumin and s-ovalbumin were compared in studies of changes in properties of ovalbumin on conversion to s-ovalbumin. Although there are 49 carboxyl groups in ovalbumin, two were not titrated in 0.25 M KCl but on conversion to s-ovalbumin. A similar change was also noted in the two carboxyl groups of ovalbumin in denaturation with guanidine hydrochloride. Liberation of carboxyl groups was noted in ovalbumin samples which were assumed to contain various amounts of intermediate and the isoelectric focusing patterns of these samples also changed. No difference was noted in the both amounts of ionizable amino groups and phenolic hydroxyl groups between ovalbumin and s-ovalbumin. This seems to show that these two groups are not concerned with the liberation of carboxyl groups during ovalbumin-s-ovalbumin transformation.