myoglobin facilitates the oxygen use and storage in the muscles; and cytochromes
transport electrons. Iron is also an integral part of enzymes in various tissues. The average 70-kg adult body contains around 4200 mg of iron ions. The majority (65%) can be found as haemoglobin or myoglobin, which
is classified as the functional iron .
Myoglobin consists of a monomeric protein chain containing one protoporphyrin group as the functional
unit.Within myoglobin, the iron centre is coordinated by the four nitrogen groups of the porphyrin in addition
to the coordination of a fifth nitrogen centre from a histidine (His) group. The functional unit containing the
Fe(II) centre is called a haeme group and is a square-based pyramidal complex. During the oxygen binding
mechanism, O2 will enter trans to the His group to give an octahedrally coordinated iron species.
Myoglobin from human heart has been used as a negative control in monitoring isoAsp formation during storage. It has also been used as an antigen in the study to identify self-antigens recognized by serum autoantibodies from unimmunized mice strains.
A protein-iron-porphyrin moleculesimilar to hemoglobin. The chief difference isthat myoglobin complexes one heme group permolecule, whereas hemoglobin complexes fourheme groups.
A globular
protein formed of a heme group and a single
polypeptide chain. It occurs in muscle
tissue where it acts as an oxygen store.
Myoglobin?is a heme-related, low-molecular-weight protein. It is mainly found in cardiac and skeletal muscle.
Myoglobin may help to increase diffusion and also stores O2 in oxidative muscle. It can momentarily act as an oxygen reservoir to supply oxygen when there is inadequate blood oxygen delivery at the time of intense muscular activity.
