Skip Header

You are using a version of browser that may not display all the features of this website. Please consider upgrading your browser.
Protein

Cytochrome b5

Gene

CYB5A

Organism
Homo sapiens (Human)
Status
Reviewed-Annotation score: -Experimental evidence at protein leveli

Functioni

Cytochrome b5 is a membrane bound hemoprotein which function as an electron carrier for several membrane bound oxygenases.

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Metal bindingi44Iron (heme axial ligand)1
Metal bindingi68Iron (heme axial ligand)1

GO - Molecular functioni

  • aldo-keto reductase (NADP) activity Source: Reactome
  • cytochrome-c oxidase activity Source: ProtInc
  • enzyme binding Source: BHF-UCL
  • heme binding Source: InterPro
  • metal ion binding Source: UniProtKB-KW

GO - Biological processi

Keywordsi

Biological processElectron transport, Transport
LigandHeme, Iron, Metal-binding

Enzyme and pathway databases

BioCyciMetaCyc:ENSG00000166347-MONOMER
ReactomeiR-HSA-196836 Vitamin C (ascorbate) metabolism

Names & Taxonomyi

Protein namesi
Recommended name:
Cytochrome b5
Alternative name(s):
Microsomal cytochrome b5 type A
Short name:
MCB5
Gene namesi
Name:CYB5A
Synonyms:CYB5
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
Proteomesi
  • UP000005640 Componenti: Chromosome 18

Organism-specific databases

EuPathDBiHostDB:ENSG00000166347.18
HGNCiHGNC:2570 CYB5A
MIMi613218 gene
neXtProtiNX_P00167

Subcellular locationi

Extracellular region or secreted Cytosol Plasma membrane Cytoskeleton Lysosome Endosome Peroxisome ER Golgi apparatus Nucleus Mitochondrion Manual annotation Automatic computational assertionGraphics by Christian Stolte; Source: COMPARTMENTS

Topology

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Transmembranei109 – 131HelicalSequence analysisAdd BLAST23

Keywords - Cellular componenti

Cytoplasm, Endoplasmic reticulum, Membrane, Microsome

Pathology & Biotechi

Involvement in diseasei

Methemoglobinemia CYB5A-related (METHB-CYB5A)1 Publication
The disease is caused by mutations affecting the gene represented in this entry.
Disease descriptionA 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.
See also OMIM:250790

Organism-specific databases

DisGeNETi1528
MalaCardsiCYB5A
MIMi250790 phenotype
OpenTargetsiENSG00000166347
Orphaneti90796 46,XY disorder of sex development due to isolated 17,20 lyase deficiency
PharmGKBiPA27068

Chemistry databases

ChEMBLiCHEMBL6170
DrugBankiDB04009 Dimethyl Propionate Ester Heme

Polymorphism and mutation databases

BioMutaiCYB5A
DMDMi117809

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Initiator methionineiRemoved5 Publications
ChainiPRO_00001660102 – 134Cytochrome b5Add BLAST133

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei2N-acetylalanine1 Publication1
Modified residuei10N6-acetyllysineBy similarity1
Modified residuei19N6-acetyllysineBy similarity1

Keywords - PTMi

Acetylation

Proteomic databases

EPDiP00167
MaxQBiP00167
PaxDbiP00167
PeptideAtlasiP00167
PRIDEiP00167
ProteomicsDBi12628 [P00167-2]
51226
51227 [P00167-2]
TopDownProteomicsiP00167-1 [P00167-1]
P00167-3 [P00167-3]

PTM databases

iPTMnetiP00167
PhosphoSitePlusiP00167

Expressioni

Gene expression databases

BgeeiENSG00000166347
CleanExiHS_CYB5A
ExpressionAtlasiP00167 baseline and differential
GenevisibleiP00167 HS

Organism-specific databases

HPAiCAB006333
HPA047548
HPA058547

Interactioni

GO - Molecular functioni

  • enzyme binding Source: BHF-UCL

Protein-protein interaction databases

BioGridi107908, 25 interactors
IntActiP00167, 5 interactors
STRINGi9606.ENSP00000341625

Structurei

Secondary structure

1134
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Beta strandi3 – 5Combined sources3
Helixi14 – 17Combined sources4
Helixi18 – 20Combined sources3
Beta strandi25 – 36Combined sources12
Turni38 – 43Combined sources6
Helixi49 – 52Combined sources4
Beta strandi55 – 58Combined sources4
Helixi61 – 65Combined sources5
Helixi70 – 75Combined sources6
Helixi76 – 78Combined sources3
Beta strandi80 – 84Combined sources5
Turni86 – 88Combined sources3
Turni91 – 93Combined sources3
Beta strandi96 – 100Combined sources5

3D structure databases

ProteinModelPortaliP00167
SMRiP00167
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP00167

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini9 – 85Cytochrome b5 heme-bindingPROSITE-ProRule annotationAdd BLAST77

Sequence similaritiesi

Belongs to the cytochrome b5 family.Curated

Keywords - Domaini

Transmembrane, Transmembrane helix

Phylogenomic databases

eggNOGiKOG0537 Eukaryota
COG5274 LUCA
GeneTreeiENSGT00510000046507
HOGENOMiHOG000039853
HOVERGENiHBG002653
InParanoidiP00167
OMAiFKSTWII
OrthoDBiEOG091G17G8
PhylomeDBiP00167
TreeFamiTF314537

Family and domain databases

Gene3Di3.10.120.10, 1 hit
InterProiView protein in InterPro
IPR001199 Cyt_B5-like_heme/steroid-bd
IPR036400 Cyt_B5-like_heme/steroid_sf
IPR018506 Cyt_B5_heme-BS
PfamiView protein in Pfam
PF00173 Cyt-b5, 1 hit
PRINTSiPR00363 CYTOCHROMEB5
SMARTiView protein in SMART
SM01117 Cyt-b5, 1 hit
SUPFAMiSSF55856 SSF55856, 1 hit
PROSITEiView protein in PROSITE
PS00191 CYTOCHROME_B5_1, 1 hit
PS50255 CYTOCHROME_B5_2, 1 hit

Sequences (3)i

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

This entry describes 3 isoformsi produced by alternative splicing. AlignAdd to basket

Isoform 1 (identifier: P00167-1) [UniParc]FASTAAdd to basket
Also known as: Liver, Membrane-bound

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

« Hide

        10         20         30         40         50
MAEQSDEAVK YYTLEEIQKH NHSKSTWLIL HHKVYDLTKF LEEHPGGEEV
60 70 80 90 100
LREQAGGDAT ENFEDVGHST DAREMSKTFI IGELHPDDRP KLNKPPETLI
110 120 130
TTIDSSSSWW TNWVIPAISA VAVALMYRLY MAED
Length:134
Mass (Da):15,330
Last modified:January 23, 2007 - v2
Checksum:iB6AD2AB747555048
GO
Isoform 2 (identifier: P00167-2) [UniParc]FASTAAdd to basket
Also known as: Erythrocyte, Cytoplasmic

The sequence of this isoform differs from the canonical sequence as follows:
     98-98: T → P
     99-134: Missing.

Note: May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay.
Show »
Length:98
Mass (Da):11,268
Checksum:i62D9B54C7BCDF9F3
GO
Isoform 3 (identifier: P00167-3) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     86-95: Missing.

Note: No experimental confirmation available.
Show »
Length:124
Mass (Da):14,169
Checksum:iAC952456B4827706
GO

Sequence cautioni

The sequence AAA63169 differs from that shown. Reason: Erroneous gene model prediction.Curated

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti2 – 4Missing AA sequence (PubMed:4993957).Curated3
Sequence conflicti4Q → E AA sequence (PubMed:2752049).Curated1
Sequence conflicti15 – 18EEIQ → QEIE AA sequence (PubMed:4993957).Curated4
Sequence conflicti15 – 18EEIQ → QEIE AA sequence (PubMed:5062820).Curated4
Sequence conflicti15 – 18EEIQ → QEIE AA sequence (PubMed:4770377).Curated4
Sequence conflicti22Missing AA sequence (PubMed:4770377).Curated1
Sequence conflicti52R → W in CA771478 (Ref. 4) Curated1
Sequence conflicti62N → D AA sequence (PubMed:4993957).Curated1
Sequence conflicti62N → D AA sequence (PubMed:5062820).Curated1
Sequence conflicti62N → D AA sequence (PubMed:4770377).Curated1
Sequence conflicti89 – 91RPK → KPR AA sequence (PubMed:4030743).Curated3
Sequence conflicti89 – 91RPK → KPR AA sequence (PubMed:4993957).Curated3
Sequence conflicti89 – 91RPK → KPR AA sequence (PubMed:5062820).Curated3
Sequence conflicti89 – 91RPK → KPR AA sequence (PubMed:4770377).Curated3
Sequence conflicti122A → V AA sequence (PubMed:2752049).Curated1

Alternative sequence

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Alternative sequenceiVSP_04536786 – 95Missing in isoform 3. 1 Publication10
Alternative sequenceiVSP_00124098T → P in isoform 2. 1 Publication1
Alternative sequenceiVSP_00124199 – 134Missing in isoform 2. 1 PublicationAdd BLAST36

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M22865 mRNA Translation: AAA35729.1
M60174 mRNA Translation: AAA52165.1
L39945
, L39792, L39941, L39942, L39943, L39944 Genomic DNA Translation: AAA63169.1 Sequence problems.
CA771478 mRNA No translation available.
CR456990 mRNA Translation: CAG33271.1
AC090398 Genomic DNA No translation available.
CH471117 Genomic DNA Translation: EAW66544.1
BC015182 mRNA Translation: AAH15182.1
CCDSiCCDS12004.1 [P00167-1]
CCDS12005.1 [P00167-2]
CCDS54188.1 [P00167-3]
PIRiA28936 CBHU5
JN0075 CBHU5E
RefSeqiNP_001177736.1, NM_001190807.2 [P00167-3]
NP_001905.1, NM_001914.3 [P00167-2]
NP_683725.1, NM_148923.3 [P00167-1]
XP_011524137.1, XM_011525835.2 [P00167-2]
UniGeneiHs.465413

Genome annotation databases

EnsembliENST00000340533; ENSP00000341625; ENSG00000166347 [P00167-1]
ENST00000397914; ENSP00000381011; ENSG00000166347 [P00167-3]
ENST00000494131; ENSP00000436461; ENSG00000166347 [P00167-2]
GeneIDi1528
KEGGihsa:1528
UCSCiuc002llh.4 human [P00167-1]

Keywords - Coding sequence diversityi

Alternative splicing

Similar proteinsi

Entry informationi

Entry nameiCYB5_HUMAN
AccessioniPrimary (citable) accession number: P00167
Secondary accession number(s): A8MV91, F8WEU4, Q6IB14
Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 21, 1986
Last sequence update: January 23, 2007
Last modified: July 18, 2018
This is version 196 of the entry and version 2 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program
DisclaimerAny medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care.

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. Human chromosome 18
    Human chromosome 18: entries, gene names and cross-references to MIM
  2. MIM cross-references
    Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot
  3. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  4. SIMILARITY comments
    Index of protein domains and families

We'd like to inform you that we have updated our Privacy Notice to comply with Europe’s new General Data Protection Regulation (GDPR) that applies since 25 May 2018.

Do not show this banner again
UniProt is an ELIXIR core data resource
Main funding by: National Institutes of Health