Figure 4. Does retinol bind to Tsp?

Tsp (1 mM) and retinol (10 mM) were mixed together and incubated to allow potential binding to occur. A shows the results of an emission wavelength scan from 380 to 550 nm while holding the excitation constant at 333 nm. The spectrum was compared with the same concentration of protein alone and 10 mM all-trans-retinol alone. The scans show that the mixture of ligand and protein was no different from the sum of the ligand alone and the protein alone, suggesting that retinol exhibited no fluorescence enhancement when mixed with the protein (indicating that Tsp does not bind retinol). B shows the results of an excitation scan while holding the emission constant at 479 nm. The results were the same as with the emission scan and showed no fluorescence enhancement of retinol in the presence of Tsp, again suggesting that retinol did not bind to Tsp.