A fluorescent probe for lipid-binding proteins; binds with high affinity to hydrophobic surfaces of proteins; ex/em = 350/520 (free) and 468-477 nM (bound), respectively; undergoes a blue shift with an increase in fluorescence intensity when bound to protein; well suited for determining the affinity of hydrophobic ligands to their corresponding binding proteins; binds to FABP2 with a Kd value of approximately 9.7 μM at 24.5°C