Free for academic non-profit institutions. Other users need a Commercial license

Aliases for CYB5R3 Gene

Aliases for CYB5R3 Gene

  • Cytochrome B5 Reductase 3 2 3
  • DIA1 3 4 6
  • B5R 3 4 6
  • Diaphorase-1 3 4
  • EC 4 63
  • NADH-Cytochrome B5 Reductase 3 Membrane-Bound Form 3
  • Diaphorase (NADH) (Cytochrome B-5 Reductase) 2
  • NADH-Cytochrome B5 Reductase 3 Soluble Form 3
  • NADH-Cytochrome B5 Reductase 3 3
  • 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 Disease and PAK Pathway. GO annotations related to this gene include flavin adenine dinucleotide binding and ADP binding. An important paralog of this gene is CYB5R1.

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

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

Epigenetics Products

  • DNA Methylation CpG Assay Predesigned for Pyrosequencing in human,mouse,rat

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

UCSC Golden Path with GeneCards custom track
Cytogenetic band:
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 Lys42, Lys120, Lys126, Lys173, Lys214, and Lys234
  • Modification sites at PhosphoSitePlus

Other Protein References for CYB5R3 Gene

Antibody Products

Domains 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:0004128 cytochrome-b5 reductase activity, acting on NAD(P)H TAS --
GO:0005515 protein binding --
GO:0016208 AMP binding IEA --
GO:0016491 oxidoreductase activity --
GO:0043531 ADP binding IEA --
genes like me logo Genes that share ontologies with CYB5R3: view

Animal Model Products

miRNA for CYB5R3 Gene

miRNA Products

Inhibitory RNA Products

  • Predesigned siRNA for gene silencing in human,mouse,rat for CYB5R3

In Situ Assay Products

Flow Cytometry Products

No data available for Phenotypes , Animal Models , Transcription Factor Targeting 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
endoplasmic reticulum 5
mitochondrion 5
cytosol 4
extracellular 2
cytoskeleton 1
golgi apparatus 1
peroxisome 1
plasma membrane 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
GO:0005741 mitochondrial outer membrane TAS --
GO:0005743 mitochondrial inner membrane IEA --
GO:0005783 endoplasmic reticulum IDA --
genes like me logo Genes that share ontologies with CYB5R3: view

Pathways for CYB5R3 Gene

SuperPathways for CYB5R3 Gene

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

Pathways by source for CYB5R3 Gene

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

PCR Array Products

  • Pathway & Disease-focused RT² Profiler PCR Arrays

Gene Ontology (GO) - Biological Process for CYB5R3 Gene

GO ID Qualified GO term Evidence PubMed IDs
GO:0006695 cholesterol biosynthetic process IEA --
GO:0006766 vitamin metabolic process TAS --
GO:0006767 water-soluble vitamin metabolic process TAS --
GO:0008015 blood circulation TAS 1400360
GO:0019852 L-ascorbic acid metabolic process TAS --
genes like me logo Genes that share ontologies with CYB5R3: view

Compounds for CYB5R3 Gene

(2) Drugbank Compounds for CYB5R3 Gene

Compound Status Synonyms Cas Number PubChem ID Type Actions PubMed IDs
Flavin adenine dinucleotide
  • Adenosine 5'-(trihydrogen pyrophosphate), 5'-5'-ester with riboflavine
146-14-5 643975 Target approved
  • 1,4-dihydronicotinamide adenine dinucleotide
606-68-8 439153 Target nutraceutical

(5) HMDB Compounds for CYB5R3 Gene

Compound Synonyms Cas Number PubMed IDs
  • 1H-Purin-6-amine flavin dinucleotide
  • 553-12-8 (FREE ACID)
  • 553-12-8 (FREE ACID)
  • 3-Carbamoyl-1-D-ribofuranosylpyridinium hydroxide 5'-ester with adenosine 5'-pyrophosphate
  • 1,4-Dihydronicotinamide adenine dinucleotide

(43) Novoseek inferred chemical compound relationships for CYB5R3 Gene

Compound -log(P) Hits PubMed IDs
benzamidoxime 88.2 4
nadh 84.3 103
sulfamethoxazole hydroxylamine 83 6
dicoumarol 65.1 3
p-hydroxymercuribenzoate 64.7 3

(3) PharmGKB related drug/compound annotations for CYB5R3 Gene

Drug/compound Annotation
methylene blue
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:

miRNA Products

Inhibitory RNA Products

  • Predesigned siRNA for gene silencing in human,mouse,rat for CYB5R3

Flow Cytometry Products

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

mRNA expression in embryonic tissues and stem cells from LifeMap Discovery

Integrated Proteomics: protein expression 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 expressions with CYB5R3: view

Expression partners for CYB5R3 Gene

* - Elite partner

Primer Products

In Situ Assay Products

No data available for 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
(Mus musculus)
Mammalia Cyb5r3 16
Cyb5r3 36
  • 86 (a)
(Bos Taurus)
Mammalia CYB5R3 36
  • 91 (a)
(Canis familiaris)
Mammalia CYB5R3 36
  • 88 (a)
(Monodelphis domestica)
Mammalia CYB5R3 36
  • 83 (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 MAF
rs137121 -- 42,617,548(+) GAAGG(C/T)CATTT downstream-variant-500B
rs137122 -- 42,617,830(+) ACCTA(C/T)CTTCT downstream-variant-500B
rs137123 -- 42,619,486(+) GTGTG(G/T)GGGGT utr-variant-3-prime
rs137124 -- 42,619,710(+) GTGAC(C/T)GGGTG utr-variant-3-prime
rs137125 -- 42,623,053(+) TTTAC(-/CGCAGTTGCCGCCAC)TCCCT intron-variant

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

Relevant External Links for CYB5R3 Gene

HapMap Linkage Disequilibrium report
Human Gene Mutation Database (HGMD)

Disorders for CYB5R3 Gene

(1) OMIM Diseases for CYB5R3 Gene (613213)


  • 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.

(4) University of Copenhagen DISEASES for CYB5R3 Gene

(10) Novoseek inferred disease relationships for CYB5R3 Gene

Disease -log(P) Hits PubMed IDs
methemoglobinemia hereditary 97.9 34
methemoglobinemia 92.6 53
methemoglobinemia acquired 70.3 2
enzyme deficiency 67.1 5
rare disease 15.5 2

Relevant External Links for CYB5R3

Genetic Association Database (GAD)
Human Genome Epidemiology (HuGE) Navigator
genes like me logo Genes that share disorders with CYB5R3: view

No data available for Genatlas for CYB5R3 Gene

Publications for CYB5R3 Gene

  1. Enzymatic instability of NADH-cytochrome b5 reductase as a cause of hereditary methemoglobinemia type I (red cell type). (PMID: 1400360) Shirabe K. … Takeshita M. (J. Biol. Chem. 1992) 3 4 23
  2. Exonic point mutations in NADH-cytochrome B5 reductase genes of homozygotes for hereditary methemoglobinemia, types I and III: putative mechanisms of tissue-dependent enzyme deficiency. (PMID: 1707593) Katsube T. … Fukumaki Y. (Am. J. Hum. Genet. 1991) 3 4 23
  3. Structural role of serine 127 in the NADH-binding site of human NADH- cytochrome b5 reductase. (PMID: 1898726) Yubisui T. … Takano T. (J. Biol. Chem. 1991) 3 4 23
  4. Role of cysteine residues in human NADH-cytochrome b5 reductase studied by site-directed mutagenesis. Cys-273 and Cys-283 are located close to the NADH-binding site but are not catalytically essential. (PMID: 2019583) Shirabe K. … Takeshita M. (J. Biol. Chem. 1991) 3 4 23
  5. Four new mutations in the NADH-cytochrome b5 reductase gene from patients with recessive congenital methemoglobinemia type II. (PMID: 7718898) Vieira L.M. … Leroux A. (Blood 1995) 3 4 23

Products for CYB5R3 Gene

Sources for CYB5R3 Gene

Back to Top