What is the effect of nitric oxide on the binding of oxygen to hemoglobin?

A Increases oxygen binding affinity
B Decreases oxygen binding affinity ✓
C Has no effect on oxygen binding affinity
D Enhances oxygen release to tissues

Explanation

Nitric oxide binds to the heme group of hemoglobin, reducing its affinity for oxygen and thereby facilitating the release of oxygen to tissues.

Source

Guyton and Hall Textbook of Medical Physiology
Hematology Hematology: Hemoglobin and Oxygen Transport Hematology: Hemoglobin and Oxygen Transport Medium MEDICAL Confidence: high