Myoglobin is an iron- and oxygen-binding
protein found in the
muscle tissue of vertebrates in general and in almost all mammals. It is related to
hemoglobin, which is the iron- and oxygen-binding protein in blood, specifically in the
red blood cells. In humans, myoglobin is only found in the bloodstream after muscle injury. It is an abnormal finding, and can be diagnostically relevant when found in blood.