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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
General
glycoprotein
membrane protein
oxidoreductase
phosphoprotein
Properties
SIZE: entity length = 286 aa
MW = 32 kD
COMPARTMENT: cellular membrane
MOTIF: transmembrane domain {12-32}
Cytochrome b561 {15-220}
MOTIF: transmembrane domain {49-69}
Iron [Fe]-binding site
SITE: 50-50
transmembrane domain {85-105}
Iron [Fe]-binding site
SITE: 86-86
Iron [Fe]-binding site
SITE: 108-108
Iron [Fe]-binding site
SITE: 120-120
transmembrane domain {123-143}
transmembrane domain {158-178}
Iron [Fe]-binding site
SITE: 159-159
transmembrane domain {199-219}
N-glycosylation site {N231}
Ser phosphorylation site {S260}
Thr phosphorylation site {T285}
Database Correlations
OMIM 605745
UniProt Q53TN4
Pfam PF03188
References
UniProt :accession Q53TN4