cytochrome b reductase 1 (duodenal cytochrome b, Ferric- chelate reductase 3) (CYBRD1 DCYTB FRRS3)

Function

• ferric-chelate reductase that reduces Fe+3 to Fe+2
• present at the brush border of duodenal enterocytes where it probably reduces dietary Fe+3 thereby facilitating its transport into the mucosal cells
• uses ascorbate as electron donor
• may be involved in extracellular ascorbate recycling in erythrocyte membranes
• may also act as a ferrireductase in airway epithelial cells

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

Structure

contains 1 cytochrome b561 domain

Compartment

membrane

Expression

• present in erythrocyte membranes (at protein level)
• also expressed in respiratory epithelium
• induced by iron deficiency (at protein level)

Pathology

• defects in CYBRD1 may be a cause of primary hereditary hemochromatosis

Laboratory

• cytochrome B reductase in amniotic fluid

More general terms

• oxidoreductase
• glycoprotein
• membrane protein
• phosphoprotein

Database

• OMIM: https://mirror.omim.org/entry/605745
• UniProt: http://www.uniprot.org/uniprot/Q53TN4.html