Interaction of pancreatic phospholipases A sub(2) and semisynthetic mutants with anionic substrates and substrate analogues

Recently it was shown that porcine pancreatic phospholipase A sub(2) aggregates in the presence of submicellar concentrations of anionic substrates. In this study the interaction process was further investigated by using pancreatic phospholipases A sub(2) of different origins and several semisynthetic mutants in which one particular amino acid residue was substituted. It is shown that the aggregation process is controlled by the ionization state of the side chains of the amino acid residues at positions 6 and 17.