Biochemistry 4th Edition by Reginald Garrett, Charles Grisham

Exercise 5

The quantitative advantage of allosteric behavior for O2-transporting heme proteins
The equation

allows the calculation of Y (the fractional saturation of hemoglobin with O2) given P 50 and n (see box on pages 500-501). Let P 50 = 26 torr and n = 2.8. Calculate Y in the lungs where pO₂ = 100 torr and Y in the capillaries where pO₂ = 40 torr. What is the efficiency of O₂ delivery under these conditions (expressed as Y lungs - Y capillaries ) Repeat the calculations, but for n = 1. Compare the values for Y lungs - Y capillaries for n = 2.8 versus Y lungs - Y capillaries for n = 1 to determine the effect of cooperative O2-binding of oxygen delivery by hemoglobin.