Fluorescent Sarcosine for Drug Binding Site 2 on Human Serum Albumin

Dansylsarcosine cyclohexylammonium salt (1) is a fluorescent probe which specifically binds to human serum albumin (HSA) drug binding site 2 (yellow).^1,2) The maximum fluorescence wavelength of 1 shifts by binding to HSA, and the fluorescence decreases by the competitive displacement of drugs and pharmaceuticals, which confirms for drugs to bind the site 2. Alternatively, dansylamide (2) binds to HSA drug binding site 1 (light blue) and is used as a fluorescent probe in a similar mechanism. Thus, a simple and quick drug binding assay can be attained with a combination of 1 and 2. In this way, 1 and 2 are useful for the characterization of the binding sites in HSA essential for the study of pharmacokinetics and pharmacological effect.