1. Institute of Organic and Pharmaceutical Chemistry and Institute of Biological Research and Biotechnology, The National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens 11635, Greece, Novo Nordisk A/S, Novo Nordisk Park, DK-2760, Måløv, Denmark, and School of Clinical Medical Sciences, Division of Diabetes, The Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom