1. Biochemistry Section, Division of Life Sciences, King's College, Campden Hill Road, London W8 7AH, UK
2. Chemistry Department, King's College, The Strand, London WC2R 2LS, UK
3. Department of Microbiology and Biotechnology, Kossuth L, University of Sciences, 4010 Debrecen, Hungary
4. Department of Paediatrics, County Hospital, Bartok B, 2-26, H-4043 Debrecen, Hungary
5. Department of Paediatrics, University Medical School of Debrecen, H-4012 Debrecen, Hungary