1. J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague 8, Czech Republic, Charles University, 3rd Faculty of Medicine, Center for Biomedical Sciences, Ruská 87, 100 00 Prague 10, Czech Republic, and Institute of Organic Chemistry and Biochemistry, Flemingovo nam. 2, 166 10 Prague 6, Czech Republic