Combination of the unique physical and chemical properties of fluorine with proteinogenic amino acids represents a new approach for the design of biologically active peptides with improved pharmacological parameters that carry a powerful label for spectroscopic analysis. However, the general consequences of amino acid fluorination on structure and activity of peptides and proteins are still controversially discussed. Studying the interaction of fluorinated amino acids with enzyme active sites provides valuable information on how fluoroalkyl groups of peptide-based drugs might interact with target proteins or receptors. Therefore, different enzymatic approaches including proteolysis studies, enzymatic resolutions and peptide bond couplings were studied by our group.