Ph.D. Thesis.
Rutgers University, New Brunswick, NJ (January 1974)
Rutgers University Library Annex – Call Number: QD.B265V
Dissertations Abstracts International B 35-01B:69 (1974)
Chemical Abstracts 81:116607
-----------
Volume Changes Accompanying the Titration of Native and Denatured Ribonuclease and Lysozyme
ABSTRACT
The volume changes produced by the reaction of hydroxyl and hydrogen ions with two proteins, hen egg white lysozyme and bovine pancreatic ribonuclease, have been measured dilatometrically.
In the native proteins, the volume change for the reaction of amino groups and hydroxyl ions is lower than it is for the same reaction in model amine compounds. Furthermore, the volume changes in this pH region (pH 5.5 to 10) are dependent in a complicated manner on the initial pH of the protein solution being titrated. A possible explanation for this pH dependence is offered.
The carboxyl groups in these proteins produced volume changes upon titration with hydroxyl and hydrogen ions that were similar to the values obtained within model carboxylic acids were titrated.
The two proteins were also oxidized with performic acid and the resulting denatured derivatives titrated dilatometrically. In contrast to the native proteins, the volume changes in the histidine and lysine regions were then independent of the initial pH. The same volume changes were obtained in the pH range 5.5 to 10, regardless of the starting pH of the titration. The histidines of denatured ribonuclease gave normal a volume change upon titration with hydroxyl ions; the volume change being close to the values observed in model compounds.