1. Institute for Physical Chemistry, University of Marburg, D-35032 Marburg, Germany, N-Zyme BioTec, c/o Technical University Darmstadt, D-64287 Darmstadt, Germany, and Fachbereich Chemische Technologie, Fachhochschule Darmstadt, Hochschulstrasse 2, D-64289 Darmstadt, Germany