heme ring

The heme ring is a crucial component in biology, primarily known as the prosthetic group within hemoglobin and myoglobin. This deep red, iron-containing structure, with the chemical formula C₃₄H₃₂N₄O₄Fe, is essential for oxygen transport in many animals.12

Each hemoglobin molecule is composed of four heme groups surrounding a globin group. The heme itself consists of a porphyrin, a ring-like organic compound, to which an iron atom is attached. It is this iron atom that binds with oxygen as blood circulates between the lungs and tissues. A single hemoglobin molecule can bind up to four oxygen molecules. The heme group's intense color is due to the porphyrin, not the iron itself.234