Hemopexin is a plasma glycoprotein that binds heme with high affinity, preventing its toxic effects and facilitating its clearance, thus playing a crucial role in iron metabolism and protection against oxidative stress.

The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.

Cell surface receptors that bind peptide messengers with high affinity and regulate intracellular signals which influence the behavior of cells.

Plasma glycoproteins that form a stable complex with hemoglobin to aid the recycling of heme iron. They are encoded in man by a gene on the short arm of chromosome 16.