What is the equilibrium constant? How many moles of ligand bind per mole of riboflavin binding protein? 0.040 mM of riboflavin binding protein was used.     

Riboflavin (ligand) mM	Absorbance
0.025	0.025
0.050	0.038
0.075	0.045
0.100	0.056
0.125	0.058
0.150	0.065

Km = 2 mM