Topic summary
Haem
Extracted from the Wikipedia article Heme.
Heme (American English), or haem (Commonwealth English, both pronounced // ), is a ring-shaped iron-containing molecule that serves as a ligand of various proteins, especially as a component ofhemoglobin, which carries oxygen in the bloodstream. It is composed of four pyrrole rings with two vinyl and two propionic acid side chains. Heme is biosynthesized in both the bone marrow and the liver.