The Saturation Game: Teaching Protein–Ligand Binding with a Playing Card Analogy

The dissociation constant of a protein–ligand complex is commonly measured by a saturation binding experiment, in which a protein is progressively saturated by repeated additions of a ligand. Students often find it hard to understand how the hyperbolic binding curve, described by the Hill–Langmuir equation, arises from an unchanging dissociation constant. In this activity, students played a prelab card game which taught them the stochastic origin of the binding curve’s shape. The saturation game almost doubled the number of students who chose the correct explanation of the curve’s shape and decreased the popularity of the most common misconception by a factor of 2.5.