Lysine residues of bovine serum albumin (BSA) have been chemically acetylated by acetic anhydride under basic conditions.  A major Ac-BSA band runs at approximately 66 KDa and Ac-BSA oligos run at approximately 120-260 KDa. NOTE: Ac-BSA oligomerization is not caused by the acetylation reaction as these species are also present in unmodified BSA as seen in a Coomassie stain of unmodified BSA protein.  Acetylated BSA is supplied as a lyophilized powder.