What protein is responsible for transporting oxygen in red blood cells?

Hemoglobin is the protein responsible for transporting oxygen in red blood cells. It is a complex protein made up of four subunits, each containing an iron atom that can bind to oxygen. This unique structure allows hemoglobin to efficiently pick up oxygen in the lungs and release it to tissues throughout the body that require it for metabolic processes.

The ability of hemoglobin to undergo conformational changes when binding to oxygen enhances its capacity to transport the gas. As hemoglobin binds to oxygen, it changes shape, which also facilitates further binding of oxygen molecules. This process is known as cooperative binding and is essential for maintaining effective oxygen delivery under varying conditions in the body, such as changes in pH or carbon dioxide levels.

In contrast, while myoglobin is another oxygen-binding protein, it is primarily found in muscle tissues and has a higher affinity for oxygen but is not involved in the transport of oxygen in the bloodstream. Albumin functions mainly as a carrier for various substances in the blood, including fatty acids and hormones, rather than transporting oxygen. Keratin is a structural protein found in hair, nails, and skin, and does not have a role in oxygen transport.