1. Reversible Binding of a Protein to a Ligand: Oxygen-Binding Proteins

• Oxygen Can Bind to a Heme Prosthetic Group

• Globins Are a Family of Oxygen-Binding Proteins

• Myoglobin Has a Single Binding Site for Oxygen

• Protein-Ligand Interactions Can Be Described Quantitatively

• Protein Structure Affects How Ligands Bind

• Hemoglobin Transports Oxygen in Blood

• Hemoglobin Subunits Are Structurally Similar to Myoglobin

• Hemoglobin Undergoes a Structural Change on Binding Oxygen

• Hemoglobin Binds Oxygen Cooperatively

• Cooperative Ligand Binding Can Be Described Quantitatively

• BOX 5-1 Carbon Monoxide: A Stealthy Killer

• Two Models Suggest Mechanisms for Cooperative Binding

• Hemoglobin Also Transports H+ and CO2

• Oxygen Binding to Hemoglobin Is Regulated by 2,3-Bisphosphoglycerate

• Sickle Cell Anemia Is a Molecular Disease of Hemoglobin