Question

1. Which of the following situations would produce a Hill plot with n < 1.0? Explain your reasoning in each case.
2. 1. Hb binding of oxygen when concentrations of O₂ and CO are equal.

Answer 1

Answer:

When concentrations of O2 and CO are equal, Hemoglobin binding of oxygen would produce a Hill plot with n < 1.0.

A Hill plot is used to get quantitative measure of cooperativity of ligand binding. For example for Hemoglobin molecule, a Hill plot can provide information on the degree of cooperativity for oxygen binding to hemoglobin.

The slope value in a Hill plot is denoted by N.

N > 1 indicates positive cooperativity

N < 1 indicates negative cooperativity

N = 1, Non-Cooperative binding (independent binding)

Carbon monoxide is a competitive inhibitor to oxygen and has high affinity for binding to heme group of hemoglobin. Therefore, When the concentrations of O2 and CO are equal. In negative cooperativity,the binding of one molecule of ligand impedes the binding of others.