1. CIISA-Faculdade de Medicina Veterinária, Pólo Universitário do Alto da Ajuda, Rua Professor Cid dos Santos, 1300-477 Lisboa, Portugal1
2. Department of Biological and Nutritional Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, UK2
3. Laboratory of Molecular Enzymology, The Babraham Institute, Babraham, Cambridge CB2 4AT, UK3