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Aliases for CYB5R3 Gene

Aliases for CYB5R3 Gene

  • Cytochrome B5 Reductase 3 2 3 5
  • Diaphorase-1 3 4
  • EC 4 63
  • DIA1 3 4
  • B5R 3 4
  • NADH-Cytochrome B5 Reductase 3 Membrane-Bound Form 3
  • Diaphorase (NADH) (Cytochrome B-5 Reductase) 2
  • NADH-Cytochrome B5 Reductase 3 Soluble Form 3
  • Mutant NADH-Cytochrome B5 Reductase 3
  • NADH-Cytochrome B5 Reductase 3 2
  • Cytochrome B5 Reductase 4

External Ids for CYB5R3 Gene

Previous HGNC Symbols for CYB5R3 Gene

  • DIA1

Previous GeneCards Identifiers for CYB5R3 Gene

  • GC22M041340
  • GC22M043014
  • GC22M025974

Summaries for CYB5R3 Gene

Entrez Gene Summary for CYB5R3 Gene

  • This gene encodes cytochrome b5 reductase, which includes a membrane-bound form in somatic cells (anchored in the endoplasmic reticulum, mitochondrial and other membranes) and a soluble form in erythrocytes. The membrane-bound form exists mainly on the cytoplasmic side of the endoplasmic reticulum and functions in desaturation and elongation of fatty acids, in cholesterol biosynthesis, and in drug metabolism. The erythrocyte form is located in a soluble fraction of circulating erythrocytes and is involved in methemoglobin reduction. The membrane-bound form has both membrane-binding and catalytic domains, while the soluble form has only the catalytic domain. Alternate splicing results in multiple transcript variants. Mutations in this gene cause methemoglobinemias. [provided by RefSeq, Jan 2010]

GeneCards Summary for CYB5R3 Gene

CYB5R3 (Cytochrome B5 Reductase 3) is a Protein Coding gene. Diseases associated with CYB5R3 include Methemoglobinemia, Type I and Recessive Hereditary Methemoglobinemia Type 1. Among its related pathways are Metabolism of water-soluble vitamins and cofactors and Metabolism. GO annotations related to this gene include oxidoreductase activity and NAD binding. An important paralog of this gene is CYB5R2.

UniProtKB/Swiss-Prot for CYB5R3 Gene

  • Desaturation and elongation of fatty acids, cholesterol biosynthesis, drug metabolism, and, in erythrocyte, methemoglobin reduction.

Gene Wiki entry for CYB5R3 Gene

No data available for Tocris Summary , PharmGKB "VIP" Summary , fRNAdb sequence ontologies and piRNA Summary for CYB5R3 Gene

Genomics for CYB5R3 Gene

Regulatory Elements for CYB5R3 Gene

Enhancers for CYB5R3 Gene
GeneHancer Identifier Score Enhancer Sources TSS distance (kb) Number of Genes Away Size (kb) Transcription Factor Binding Sites within enhancer Other Gene Targets for Enhancer

Enhancers around CYB5R3 on UCSC Golden Path with GeneCards custom track

Promoters for CYB5R3 Gene
Ensembl Regulatory Elements (ENSRs) TSS Distance (bp) Size (bp) Binding Sites for Transcription Factors within promoters

ENSRs around CYB5R3 on UCSC Golden Path with GeneCards custom track

Transcription factor binding sites by QIAGEN in the CYB5R3 gene promoter:

Genomic Location for CYB5R3 Gene

42,617,840 bp from pter
42,649,568 bp from pter
31,729 bases
Minus strand

Genomic View for CYB5R3 Gene

Genes around CYB5R3 on UCSC Golden Path with GeneCards custom track

Cytogenetic band:
CYB5R3 Gene in genomic location: bands according to Ensembl, locations according to GeneLoc (and/or Entrez Gene and/or Ensembl if different)
Genomic Location for CYB5R3 Gene
GeneLoc Logo Genomic Neighborhood Exon StructureGene Density

RefSeq DNA sequence for CYB5R3 Gene

Proteins for CYB5R3 Gene

  • Protein details for CYB5R3 Gene (UniProtKB/Swiss-Prot)

    Protein Symbol:
    Recommended name:
    NADH-cytochrome b5 reductase 3
    Protein Accession:
    Secondary Accessions:
    • B1AHF2
    • B7Z7L3
    • O75675
    • Q8TDL8
    • Q8WTS8
    • Q9UEN4
    • Q9UEN5
    • Q9UL55
    • Q9UL56

    Protein attributes for CYB5R3 Gene

    301 amino acids
    Molecular mass:
    34235 Da
    Name=FAD; Xref=ChEBI:CHEBI:57692;
    Quaternary structure:
    • Component of a complex composed of cytochrome b5, NADH-cytochrome b5 reductase (CYB5R3) and MOSC2.

    Three dimensional structures from OCA and Proteopedia for CYB5R3 Gene

    Alternative splice isoforms for CYB5R3 Gene


neXtProt entry for CYB5R3 Gene

Proteomics data for CYB5R3 Gene at MOPED

Post-translational modifications for CYB5R3 Gene

  • Ubiquitination at Lys 42, Lys 120, Lys 126, Lys 173, Lys 214, and Lys 234
  • Modification sites at PhosphoSitePlus

Domains & Families for CYB5R3 Gene

Suggested Antigen Peptide Sequences for CYB5R3 Gene

Graphical View of Domain Structure for InterPro Entry



  • Contains 1 FAD-binding FR-type domain.
  • Belongs to the flavoprotein pyridine nucleotide cytochrome reductase family.
  • Contains 1 FAD-binding FR-type domain.
  • Belongs to the flavoprotein pyridine nucleotide cytochrome reductase family.
genes like me logo Genes that share domains with CYB5R3: view

No data available for Gene Families for CYB5R3 Gene

Function for CYB5R3 Gene

Molecular function for CYB5R3 Gene

UniProtKB/Swiss-Prot CatalyticActivity:
NADH + 2 ferricytochrome b5 = NAD(+) + H(+) + 2 ferrocytochrome b5.
UniProtKB/Swiss-Prot Function:
Desaturation and elongation of fatty acids, cholesterol biosynthesis, drug metabolism, and, in erythrocyte, methemoglobin reduction.

Enzyme Numbers (IUBMB) for CYB5R3 Gene

Gene Ontology (GO) - Molecular Function for CYB5R3 Gene

GO ID Qualified GO term Evidence PubMed IDs
GO:0016208 AMP binding IEA --
GO:0016491 oxidoreductase activity IEA --
genes like me logo Genes that share ontologies with CYB5R3: view
genes like me logo Genes that share phenotypes with CYB5R3: view

Human Phenotype Ontology for CYB5R3 Gene

HPO Id HPO Name Alternative Ids Definition Synonyms

Animal Model Products

No data available for Animal Models , Transcription Factor Targets and HOMER Transcription for CYB5R3 Gene

Localization for CYB5R3 Gene

Subcellular locations from UniProtKB/Swiss-Prot for CYB5R3 Gene

Isoform 1: Endoplasmic reticulum membrane; Lipid-anchor; Cytoplasmic side. Mitochondrion outer membrane; Lipid-anchor; Cytoplasmic side.
Isoform 2: Cytoplasm. Note=Produces the soluble form found in erythrocytes.

Subcellular locations from

Jensen Localization Image for CYB5R3 Gene COMPARTMENTS Subcellular localization image for CYB5R3 gene
Compartment Confidence
cytosol 5
endoplasmic reticulum 5
extracellular 5
mitochondrion 5
golgi apparatus 2
plasma membrane 2
peroxisome 1

Gene Ontology (GO) - Cellular Components for CYB5R3 Gene

GO ID Qualified GO term Evidence PubMed IDs
GO:0005737 cytoplasm TAS 9207238
GO:0005739 mitochondrion IDA 20833797
genes like me logo Genes that share ontologies with CYB5R3: view

Pathways & Interactions for CYB5R3 Gene

genes like me logo Genes that share pathways with CYB5R3: view

Pathways by source for CYB5R3 Gene

1 KEGG pathway for CYB5R3 Gene
1 GeneGo (Thomson Reuters) pathway for CYB5R3 Gene
1 Qiagen pathway for CYB5R3 Gene

Gene Ontology (GO) - Biological Process for CYB5R3 Gene

GO ID Qualified GO term Evidence PubMed IDs
GO:0006766 vitamin metabolic process TAS --
GO:0006767 water-soluble vitamin metabolic process TAS --
genes like me logo Genes that share ontologies with CYB5R3: view

No data available for SIGNOR curated interactions for CYB5R3 Gene

Drugs & Compounds for CYB5R3 Gene

(26) Drugs for CYB5R3 Gene - From: DrugBank, PharmGKB, HMDB, and Novoseek

Name Status Disease Links Group Role Mechanism of Action Clinical Trials
FAD Approved Pharma Target 0
Metoclopramide Approved, Investigational Pharma Dopamine receptor antagonist 104
Primaquine Approved Pharma 72
Rasburicase Approved, Investigational Pharma 25
NADH Nutra Target 0

(25) Additional Compounds for CYB5R3 Gene - From: Novoseek and HMDB

Name Synonyms Role CAS Number PubChem IDs PubMed IDs
  • 553-12-8 (FREE ACID)
  • Ferrocytochrome b-561
  • H2ppIX
  • HEM
  • Kammerer'S porphyrin
Hydrogen Ion
  • Hydrogen cation
  • Hydron
  • Proton
genes like me logo Genes that share compounds with CYB5R3: view

Transcripts for CYB5R3 Gene

Unigene Clusters for CYB5R3 Gene

Cytochrome b5 reductase 3:
Representative Sequences:

Alternative Splicing Database (ASD) splice patterns (SP) for CYB5R3 Gene

ExUns: 1a · 1b · 1c ^ 2 ^ 3 ^ 4 ^ 5a · 5b ^ 6 ^ 7a · 7b ^ 8a · 8b ^ 9 ^ 10a · 10b ^ 11a · 11b · 11c · 11d
SP1: - - - - -
SP2: - - - - - -
SP3: - - - - - - - - -
SP4: - -
SP5: - -
SP6: -

Relevant External Links for CYB5R3 Gene

GeneLoc Exon Structure for
ECgene alternative splicing isoforms for

Expression for CYB5R3 Gene

mRNA expression in normal human tissues for CYB5R3 Gene

Integrated Proteomics: protein expression in normal tissues and cell lines from ProteomicsDB, PaxDb, MOPED, and MaxQB for CYB5R3 Gene

SOURCE GeneReport for Unigene cluster for CYB5R3 Gene Hs.561064

mRNA Expression by UniProt/SwissProt for CYB5R3 Gene

Tissue specificity: Isoform 2 is expressed at late stages of erythroid maturation.
genes like me logo Genes that share expression patterns with CYB5R3: view

Protein tissue co-expression partners for CYB5R3 Gene

- Elite partner

Primer Products

No data available for mRNA expression in embryonic tissues and stem cells from LifeMap Discovery , mRNA differential expression in normal tissues and Protein differential expression in normal tissues for CYB5R3 Gene

Orthologs for CYB5R3 Gene

This gene was present in the common ancestor of eukaryotes.

Orthologs for CYB5R3 Gene

Organism Taxonomy Gene Similarity Type Details
(Bos Taurus)
Mammalia CYB5R3 36
  • 91 (a)
(Canis familiaris)
Mammalia CYB5R3 36
  • 88 (a)
(Monodelphis domestica)
Mammalia CYB5R3 36
  • 83 (a)
(Mus musculus)
Mammalia Cyb5r3 36
  • 86 (a)
(Ornithorhynchus anatinus)
Mammalia CYB5R3 36
  • 71 (a)
(Pan troglodytes)
Mammalia CYB5R3 36
  • 95 (a)
(Gallus gallus)
Aves CYB5R3 36
  • 72 (a)
(Anolis carolinensis)
Reptilia CYB5R3 36
  • 73 (a)
(Danio rerio)
Actinopterygii -- 35
cyb5r3 36
  • 72 (a)
rainbow trout
(Oncorhynchus mykiss)
Actinopterygii Omy.1357 35
fruit fly
(Drosophila melanogaster)
Insecta CG5946 36
  • 53 (a)
(Caenorhabditis elegans)
Secernentea hpo-19 36
  • 52 (a)
T05H4.4 36
  • 54 (a)
baker's yeast
(Saccharomyces cerevisiae)
Saccharomycetes AIM33 36
  • 28 (a)
CBR1 36
  • 33 (a)
PGA3 36
  • 29 (a)
(Oryza sativa)
Liliopsida Os.4717 35
(Zea mays)
Liliopsida Zm.4080 35
sea squirt
(Ciona intestinalis)
Ascidiacea Cin.4536 35
Species with no ortholog for CYB5R3:
  • A. gosspyii yeast (Ashbya gossypii)
  • Actinobacteria (Mycobacterium tuberculosis)
  • African clawed frog (Xenopus laevis)
  • African malaria mosquito (Anopheles gambiae)
  • Alicante grape (Vitis vinifera)
  • alpha proteobacteria (Wolbachia pipientis)
  • amoeba (Dictyostelium discoideum)
  • Archea (Pyrococcus horikoshii)
  • barley (Hordeum vulgare)
  • beta proteobacteria (Neisseria meningitidis)
  • bread mold (Neurospora crassa)
  • Chromalveolata (Phytophthora infestans)
  • common water flea (Daphnia pulex)
  • E. coli (Escherichia coli)
  • filamentous fungi (Aspergillus nidulans)
  • Firmicute bacteria (Streptococcus pneumoniae)
  • fission yeast (Schizosaccharomyces pombe)
  • green algae (Chlamydomonas reinhardtii)
  • honey bee (Apis mellifera)
  • K. lactis yeast (Kluyveromyces lactis)
  • loblloly pine (Pinus taeda)
  • malaria parasite (Plasmodium falciparum)
  • medicago trunc (Medicago Truncatula)
  • moss (Physcomitrella patens)
  • orangutan (Pongo pygmaeus)
  • pig (Sus scrofa)
  • rat (Rattus norvegicus)
  • rice blast fungus (Magnaporthe grisea)
  • schistosome parasite (Schistosoma mansoni)
  • sea anemone (Nematostella vectensis)
  • sea urchin (Strongylocentrotus purpuratus)
  • sorghum (Sorghum bicolor)
  • soybean (Glycine max)
  • stem rust fungus (Puccinia graminis)
  • sugarcane (Saccharum officinarum)
  • thale cress (Arabidopsis thaliana)
  • tomato (Lycopersicon esculentum)
  • toxoplasmosis (Toxoplasma gondii)
  • Trichoplax (Trichoplax adhaerens)
  • tropical clawed frog (Silurana tropicalis)
  • wheat (Triticum aestivum)

Evolution for CYB5R3 Gene

Gene Tree for CYB5R3 (if available)
Gene Tree for CYB5R3 (if available)

Paralogs for CYB5R3 Gene

Paralogs for CYB5R3 Gene

(4) SIMAP similar genes for CYB5R3 Gene using alignment to 2 proteins:

genes like me logo Genes that share paralogs with CYB5R3: view

Variants for CYB5R3 Gene

Polymorphic Variants from UniProtKB/Swiss-Prot for CYB5R3 Gene

Ser-117 seems to only be found in persons of African origin. The allele frequency is 0.23 in African Americans. It was not found in Caucasians, Asians, Indo-Aryans, or Arabs. There seems to be no effect on the enzyme activity.

Sequence variations from dbSNP and Humsavar for CYB5R3 Gene

SNP ID Clin Chr 22 pos Sequence Context AA Info Type
VAR_004619 Methemoglobinemia CYB5R3-related (METHB-CYB5R3)
rs121965009 Methemoglobinemia CYB5R3-related (METHB-CYB5R3) 42,630,899(-) GCTTC(A/G)TGGAC reference, missense
VAR_004621 Methemoglobinemia CYB5R3-related (METHB-CYB5R3)
VAR_004622 Methemoglobinemia CYB5R3-related (METHB-CYB5R3)
VAR_010750 Methemoglobinemia CYB5R3-related (METHB-CYB5R3)

Structural Variations from Database of Genomic Variants (DGV) for CYB5R3 Gene

Variant ID Type Subtype PubMed ID
dgv1407e1 CNV Complex 17122850
nsv428391 CNV Gain 18775914
essv4940 CNV CNV 17122850
essv20414 CNV CNV 17122850
nsv524028 CNV Loss 19592680
nsv915180 CNV Loss 21882294
dgv4983n71 CNV Loss 21882294
dgv260n21 CNV Loss 19592680
esv2438931 CNV Deletion 19546169
nsv915185 CNV Gain 21882294

Variation tolerance for CYB5R3 Gene

Residual Variation Intolerance Score: 50.1% of all genes are more intolerant (likely to be disease-causing)
Gene Damage Index Score: 5.46; 71.56% of all genes are more intolerant (likely to be disease-causing)

Relevant External Links for CYB5R3 Gene

Human Gene Mutation Database (HGMD)

Disorders for CYB5R3 Gene

MalaCards: The human disease database

(9) MalaCards diseases for CYB5R3 Gene - From: OMIM, GeneTests, Orphanet, Swiss-Prot, DISEASES, Novoseek, and GeneCards

Disorder Aliases PubMed IDs
methemoglobinemia, type i
  • methemoglobinemia, type ii
recessive hereditary methemoglobinemia type 1
  • nadh-cytochrome b5reductase deficiency type 1
recessive hereditary methemoglobinemia type 2
  • nadh-cytochrome b5reductase deficiency type 2
hereditary methemoglobinemia
  • congenital methemoglobinemia
- elite association - COSMIC cancer census association via MalaCards


  • Methemoglobinemia CYB5R3-related (METHB-CYB5R3) [MIM:250800]: A form of methemoglobinemia, a hematologic disease characterized by the presence of excessive amounts of methemoglobin in blood cells, resulting in decreased oxygen carrying capacity of the blood, cyanosis and hypoxia. There are two types of methemoglobinemia CYB5R3-related. In type 1, the defect affects the soluble form of the enzyme, is restricted to red blood cells, and causes well-tolerated methemoglobinemia. In type 2, the defect affects both the soluble and microsomal forms of the enzyme and is thus generalized, affecting red cells, leukocytes and all body tissues. Type 2 methemoglobinemia is associated with mental deficiency and other neurologic symptoms. {ECO:0000269 PubMed:10807796, ECO:0000269 PubMed:12393396, ECO:0000269 PubMed:1400360, ECO:0000269 PubMed:15622768, ECO:0000269 PubMed:1707593, ECO:0000269 PubMed:1898726, ECO:0000269 PubMed:7718898, ECO:0000269 PubMed:8119939, ECO:0000269 PubMed:9695975, ECO:0000269 PubMed:9886302}. Note=The disease is caused by mutations affecting the gene represented in this entry.

Relevant External Links for CYB5R3

Genetic Association Database (GAD)
Human Genome Epidemiology (HuGE) Navigator
Atlas of Genetics and Cytogenetics in Oncology and Haematology:
genes like me logo Genes that share disorders with CYB5R3: view

No data available for Genatlas for CYB5R3 Gene

Publications for CYB5R3 Gene

  1. The organization and the complete nucleotide sequence of the human NADH-cytochrome b5 reductase gene. (PMID: 2479590) Tomatsu S. … Sakaki Y. (Gene 1989) 2 3 4 67
  2. Cytochrome b5 and NADH cytochrome b5 reductase: genotype-phenotype correlations for hydroxylamine reduction. (PMID: 19997042) Sacco J.C. … Trepanier L.A. (Pharmacogenet. Genomics 2010) 3 23
  3. Effects of aging on antioxidant response and phagocytosis in senescent erythrocytes. (PMID: 19811411) Brajovich M.L. … Racca A. (Immunol. Invest. 2009) 3 23
  4. Recessive hereditary methemoglobinemia: two novel mutations in the NADH-cytochrome b5 reductase gene. (PMID: 18343696) Fermo E. … Zanella A. (Blood Cells Mol. Dis. 2008) 3 23
  5. Structure and properties of the recombinant NADH-cytochrome b5 reductase of Physarum polycephalum. (PMID: 17341833) Ikegami T. … Yubisui T. (Biosci. Biotechnol. Biochem. 2007) 23 25

Products for CYB5R3 Gene

Sources for CYB5R3 Gene