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myoglobin

File:ChimeraX_rendering_of_myoglobin_(PDB_2SPL).png · Wikimedia Commons · See Wikimedia Commons

ProteinQ192642· pop 50· linked from 362 articles

Also known as MB, uniprot:P02144

Myoglobin (symbol Mb or MB) is an iron- and oxygen-binding protein found in the cardiac and skeletal muscle tissue of vertebrates in general and in almost all mammals. Myoglobin is distantly related to hemoglobin. Compared to hemoglobin, myoglobin has a higher affinity for oxygen and does not have cooperative binding with oxygen like hemoglobin does. Myoglobin consists of non-polar amino acids at the core of the globulin, where the heme group is non-covalently bounded with the surrounding polypeptide of myoglobin. In humans, myoglobin is found in the bloodstream only after muscle injury.

Protein · UniProt

Myoglobin

Gene
MB
Organism
Homo sapiens (Human)
Length
154 aa
Molecular mass
17,184 Da
Evidence
1: Evidence at protein level

Monomeric heme protein which primary function is to store oxygen and facilitate its diffusion within muscle tissues. Reversibly binds oxygen through a pentacoordinated heme iron and enables its timely and efficient release as needed during periods of heightened demand (PubMed:30918256, PubMed:34679218). Depending on the oxidative conditions of tissues and cells, and in addition to its ability to bind oxygen, it also has a nitrite reductase activity whereby it regulates the production of bioactive nitric oxide (PubMed:32891753). Under stress conditions, like hypoxia and anoxia, it also prote…

3D-structureCytoplasmDirect protein sequencingDisease variantHemeIronMetal-bindingMuscle protein
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5 registered

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Commons category
Myoglobin
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~8 min read

Article

9 sections
Contents
  • Differences from hemoglobin
  • Role in cuisine
  • Role in disease
  • Structure and bonding
  • Synthetic analogues
  • See also
  • References
  • Further reading
  • External links

Myoglobin (symbol Mb or MB) is an iron- and oxygen-binding protein found in the cardiac and skeletal muscle tissue of vertebrates in general and in almost all mammals. Myoglobin is distantly related to hemoglobin. Compared to hemoglobin, myoglobin has a higher affinity for oxygen and does not have cooperative binding with oxygen like hemoglobin does. Myoglobin consists of non-polar amino acids at the core of the globulin, where the heme group is non-covalently bounded with the surrounding polypeptide of myoglobin. In humans, myoglobin is found in the bloodstream only after muscle injury.

High concentrations of myoglobin in muscle cells allow organisms to hold their breath for a longer period of time. Diving mammals such as whales and seals have muscles with particularly high abundance of myoglobin. Myoglobin is found in Type I muscle, Type II A, and Type II B; although many older texts describe myoglobin as not found in smooth muscle, this has proved erroneous: there is also myoglobin in smooth muscle cells.

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