Protein:Ligand Saturation Equation: Example #2

The video tutorial explains how to determine ligand concentration using a formula involving Theta, the percentage of protein binding sites occupied by the ligand, and the dissociation constant (KD). The instructor demonstrates the process of rewriting the formula to solve for ligand concentration, providing a step-by-step calculation example. The tutorial concludes with a brief introduction to the Hill plot, which will be covered in the next video.

What does Theta represent in the context of ligand binding?

• The concentration of the ligand

• The total number of ligands

• The percentage of binding sites occupied

• The dissociation constant

Which of the following is the correct rearranged formula to solve for ligand concentration?

• Ligand concentration = Theta / (KD + 1)

• Ligand concentration = Theta * KD / (1 - Theta)

• Ligand concentration = KD / (Theta + 1)

• Ligand concentration = (1 - Theta) / (Theta * KD)

What is the first step in rearranging the formula to solve for ligand concentration?

• Subtract KD from both sides

• Divide both sides by Theta

• Multiply both sides by the denominator

• Add Theta to both sides

In the example calculation, what is the value of Theta in decimal form?

• 1.0

• 0.8

• 0.6

• 0.4

What is the calculated ligand concentration that results in 60% of binding sites being occupied?

• 4 micromolar

• 5 micromolar

• 7 micromolar

• 6 micromolar