myoglobin

Globular protein, closely related to haemoglobin and located in vertebrate muscle. Oxygen binds to myoglobin and is released only when the haemoglobin can no longer supply adequate oxygen to muscle cells.

Myoglobin was the very first protein to have its detailed molecular structure solved by X-ray crystallography. The English biochemist John Kendrew reported this structure in 1960, beating his Cambridge colleague Max Perutz who studied the structure of the larger haemoglobin molecule. Both shared the Nobel Prize for Chemistry in 1962.