Modified bovine serum albumin. IV. Characterization and immunochemical studies of the O-acetylated derivative

• 1.1. The reaction of bovine serum albumin (BSA) with acetic anhydride in trifluoroacetic acid medium resulted in a product in which about eight tyrosines and five aliphatic hydroxyls were esterified. There was evidence of other side reactions and some irreversible structural changes.
• 2.2. Studies on the reaction of the derivative with antibodies produced against native BSA suggest that phenolic groups of BSA may not be necessary for the BSA-anti-BSA interaction.
• 3.3. Studies with antibodies produced against O-acetyl BSA reveal that the ester group was not a major determinant in the antibody synthesis. The specificity of the antibodies progressively became broadened with prolonged immunization.
• 4.4. The difficulties in evaluating data from immunochemical studies of chemically modified proteins and the bearing of the above findings on the mechanism of interaction of protein antigens with their antibodies are discussed.