Fluorescence emission spectra of a 5 × 10−8 M solution of RG-C14:0 in 0.01 M sodium phosphate, pH 7.7 (lowest trace), and in the presence of BSA at different concentrations (from top to bottom trace, 3.5 × 10−6, 8.6 × 10−7, and 3.3 × 10−7 M). (Insert) Titration of a 5 × 10−8 M solution of RG-C14:0 in 0.01 M sodium phosphate, pH 7.7, with BSA. The solid line is a theoretical titration curve for a single binding site on the protein with Ka = 1.3 × 106.