Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7558200 | Analytical Biochemistry | 2015 | 6 Pages |
Abstract
We expand the spectroscopic utility of a well-known infrared and fluorescence probe, p-cyanophenylalanine, by showing that it can also serve as a pH sensor. This new application is based on the notion that the fluorescence quantum yield of this unnatural amino acid, when placed at or near the N-terminal end of a polypeptide, depends on the protonation status of the N-terminal amino group of the peptide. Using this pH sensor, we are able to determine the N-terminal pKa values of nine tripeptides and also the membrane penetration kinetics of a cell-penetrating peptide. Taken together, these examples demonstrate the applicability of using this unnatural amino acid fluorophore to study pH-dependent biological processes or events that accompany a pH change.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Ileana M. Pazos, Ismail A. Ahmed, Mariana I. León BerrÃos, Feng Gai,