1. D. Kern, G. Kern, H. Neef, K. Tittmann, M. Killenberg-Jabs, G. Hübner, Institut für Biochemie, Martin-Luther Universität Halle-Wittenberg, Kurt-Mothes-Straße 3, D-06120 Halle, Germany.
2. C. Wikner and G. Schneider, Karolinska Institutet, Department of Medical Biochemistry and Biophysics, Doktorsringen 4, S-17177 Stockholm, Sweden.