Laboratory of Biotransformation, Institute of Microbiology, Academy of Sciences of the Czech Republic, Videnska 1083, 14220, Praha 4, Czech Republic. kren@biomed.cas.cz.|Department of Life Science, Research Center for Biomolecules and Biosystems, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu 156-756, Seoul, Korea. hahny@cau.ac.kr.