Myoglobin: Proteins and Enzymes

Myoglobin is a cytoplasmic protein expressed in myocytes of the heart and skeletal muscle that reversibly binds oxygen. Its name derives from its structural and functional similarity to hemoglobin, the oxygen binding protein found in red blood cells. Functions of myoglobin include oxygen storage and transport, as well as scavenging of NO and reactive oxygen species. Myoglobin also serves as a sensitive marker for muscle injury resulting from cardiac infarction. Surprisingly, mice in which myoglobin has been removed by gene targeting are able to perform extensive exercise and respond normally to hypoxic challenge.