cytochrome b (ubiquinol-cytochrome-c reductase complex cytochrome b subunit, cytochrome b-c1 complex subunit 3, complex 3 subunit 3, MT-CYB, COB, CYTB, MTCYB)

Function

• component of the ubiquinol-cytochrome c reductase complex (complex 3 or cytochrome b-c1 complex)

Cofactor: binds 2 heme groups non-covalently (putative)

Structure

belongs to the cytochrome b family

Compartment

• mitochondrial inner membrane

Pathology

• defects in MT-CYB are a rare cause of mitochondrial dysfunction underlying different myopathies, including
  • mitochondrial encephalomyopathy
  • hypertrophic cardiomyopathy
  • sporadic mitochondrial myopathy
• defects in MT-CYB are the cause of histiocytoid cardiomyopathy
• defects in MT-CYB contribute to Leber hereditary optic neuropathy

Notes

• Heme 1 (or BL or b562) is low-potential & absorbs at about 562 nm, & heme 2 (or BH or b566) is high-potential & absorbs at about 566 nm (putative)

Also see cytochrome b560 (also referred to as cytochrome B.)

More general terms

• transmembrane 8 protein
• cytochrome
• mitochondrial membrane protein

Database

• OMIM: https://mirror.omim.org/entry/500000
• OMIM: https://mirror.omim.org/entry/516020
• OMIM: https://mirror.omim.org/entry/535000
• UniProt: http://www.uniprot.org/uniprot/P00156.html