CHARACTERIZATION AND PRELIMINARY-X-RAY DIFFRACTION ANALYSIS OF HUMAN PANCREATIC PROCARBOXYPEPTIDASE A2

Human procarboxypeptidase A2 has been expressed in a Pichia pastor is heterologous system and purified by hydrophobic interaction and anion exchange chromatographies, The hydrolytic action of carboxypeptidase A 2 on peptide substrates with different lengths and residues at the C-t erminus was analysed, and a preference towards long substrates with ar omatic amino acids in their C-terminal end, particularly tryptophan, w as found; with such substrates its activity is similar or higher than that of bovine carboxypeptidase A1. Procarboxy-peptidase A2 has been c rystallised using a vapour diffusion approach; the crystals obtained b elong to the monoclinic system, spacegroup P2(1), and present one proc arboxypeptidase A2 molecule per asymmetric unit, The crystals diffract beyond 1.8 Angstrom resolution and are suitable for detailed X-ray an alysis, (C) 1997 Federation of European Biochemical Societies.