1. Department of Biochemistry and Microbiology, Plovdiv University, 24 Tzar Asen Str., 4000-Plovdiv, Bulgaria
2. Department of Analytical Chemistry, Plovdiv University, 24 Tsar Asen Str., 4000-Plovdiv, Bulgaria
3. Department of Biological Chemistry and Molecular Modeling, Institut de Química Avançada de Catalunya, CSIC, J. Girona 18-26, 08034-Barcelona, Spain