1. Institute of Biochemistry, Odense University, Campusvej 55, DK-5230 Odense M, Denmark, August Krogh Institute, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark, Department of Chemistry, Carlsberg Laboratory, Gamle Carlsberg Vej 10, DK-2500 Copenhagen Valby, Denmark, and Enzyme Design, Novo-Nordisk A/S, Novo Allé, DK-2880 Bagsværd, Denmark