1. Analytical Biochemistry, Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Strasse 24-25, H. 25, 14476 Golm, Germany, Department of Chemistry and Centro Risonanze Magnetiche, University of Florence, Via Sacconi, 6, 50019 Sesto Fiorentino (FI), Italy, and Biosystems Technology, Wildau University of Applied Science, Bahnhofstrasse 1, 15745 Wildau, Germany