1,8-ANS

1,8-ANS is a fluorescent dye that binds with high affinity to hydrophobic surfaces of proteins.{14908,14913} 1,8-ANS has an excitation maximum of 350 nm. It has an emission maximum of 520 nm when free in solution but undergoes a blue shift with an increase in fluorescence intensity when bound to protein; for example, when bound to intestinal fatty acid binding protein (FABP2) it has emission maxima of 468-477 nm. 1,8-ANS binds to low polarity regions of protein surfaces making it well suited for determining the affinity of hydrophobic ligands to their corresponding binding proteins, such as the binding of free fatty acids to FABPs.{14908,14913,14912} 1,8-ANS binds to FABP2 with a Kd value of approximately 9.7 µM at 24.5°C.{14913}