PERTURBATION OF PROTON AND DETERGENT BINDING SITES IN BOVINE SERUM ALBUMIN BY ACETIMIDATION

Modification of bovine serum albumin by blocking the 57 lysine residues with methyl acetimidate hydrochloride leads to a protein with identical circular dichroism spectra with that of the native macromolecule but a slightly increased intrinsic viscosity. The binding isotherm of sodium dodecyl sulfate to both protein species is identical. However, the binding-induced difference spectra are reduced in magnitude when the ligand interacts with the modified protein. Proton binding studies indicate a larger number of carboxylate and tyrosine groups are exposed in acetimidated bovine serum albumin than in native bovine serum albumin. © 1969, American Chemical Society. All rights reserved.