Investigation of Flavin-Modified Peptides

The ability of this hydrophobic peptide environment to effect the flavin reactivity was assessed by monitoring the oxidation ofN-alkyl-l,4-dihydronicotina-mides (N-alkyl-NAH) using conditions similar to those reported in the Kaiser experiments. Under these conditions, both systems exhibited slight enhancements in the rate of oxidation of either J -benzyl-NAH or N-hexyl-NAH. Hypothesizing that the lack of performance of the system may have been due to the occlusion of the flavin from interacting with the substrate, the assays were 

The Nishino studies represented the first attempt to incorporate flavin functionality into a synthetic and structured polypeptide motif. As with the Kaiser systems, it is possible that the observed rate enhancements are a result of the association of the hydrophobic substrates with the hydrophobic core of the bundles. The use of SDS to increase accessibility to the flavin would seem to support this. However, it is also possible that the placement of the flavin into the hydrophobic core has decreased its reduction potential and that the SDS interacts with the bundle to create a slightly more hydrophilic environment for the flavin while preserving some of the hydrophobicity for substrate binding. 

---