CYB5B Gene

Name	cytochrome b5 type B (outer mitochondrial membrane)
Description	Enables heme binding activity. Contributes to nitrite reductase (NO-forming) activity. Involved in nitric oxide biosynthetic process. Located in membrane. Part of nitric-oxide synthase complex. [provided by Alliance of Genome Resources, Mar 2025]
Summary	{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n Mitochondrial cytochrome b5 type B (CYB5B) is emerging as a multifunctional redox protein implicated in several critical cellular processes. In multiple studies, CYB5B has been identified as an essential component of the mitochondrial amidoxime reductase (mARC) system, where—in conjunction with mARC and NADH cytochrome b5 reductase—it drives the reduction of N‐hydroxylated substrates. This activity appears important not only for the bioactivation of prodrugs and detoxification pathways but also for maintaining lipid homeostasis under lipogenic conditions."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "3"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Structural investigations have revealed that CYB5B displays unique packing and heme‐binding properties distinct from microsomal cytochrome b5 isoforms. These differences, characterized by variations in hydrophobic core organization and redox dynamics, tailor CYB5B’s function to the specialized mitochondrial environment."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Beyond its role in redox metabolism, CYB5B has been implicated in disease pathogenesis. Its gene amplification and cell surface overexpression in Hodgkin and aggressive Non‐Hodgkin lymphomas suggest a potential utility as a therapeutic target in these malignancies."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": " Furthermore, studies in steroidogenic contexts indicate that CYB5B modulates cytochrome P450 enzyme activities, influencing key steps in steroid hormone biosynthesis—a function that differentiates it from the microsomal isoform CYB5A."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "7"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n CYB5B also engages in protein–protein interactions with viral components such as HIV‐1 Nef, which may contribute to viral pathogenesis by perturbing host membrane processes."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "9"}]}, {"type": "t", "text": " In addition, its robust and specific membrane localization has been exploited in immunomagnetic approaches for mitochondrial isolation, underscoring its versatility as both a functional protein and a biomarker."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "10"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Collectively, these findings support a model in which CYB5B integrates redox biochemistry, lipid and steroid metabolism, and cellular signaling. Its central role in the mARC-dependent N-reductive pathway, along with its contribution to the regulation of steroidogenic enzymes and interaction with pathogenic viral proteins, highlights its potential as a biomarker and therapeutic target in diverse human diseases.\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Etienne P A Neve, Asa Nordling, Tommy B Andersson, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Amidoxime reductase system containing cytochrome b5 type B (CYB5B) and MOSC2 is of importance for lipid synthesis in adipocyte mitochondria."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Biol Chem (2012)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1074/jbc.M111.328237"}], "href": "https://doi.org/10.1074/jbc.M111.328237"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "22203676"}], "href": "https://pubmed.ncbi.nlm.nih.gov/22203676"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Birte Plitzko, Gudrun Ott, Debora Reichmann, et al. "}, {"type": "b", "children": [{"type": "t", "text": "The involvement of mitochondrial amidoxime reducing components 1 and 2 and mitochondrial cytochrome b5 in N-reductive metabolism in human cells."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Biol Chem (2013)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1074/jbc.M113.474916"}], "href": "https://doi.org/10.1074/jbc.M113.474916"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "23703616"}], "href": "https://pubmed.ncbi.nlm.nih.gov/23703616"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Gudrun Ott, Antje Havemeyer, Bernd Clement "}, {"type": "b", "children": [{"type": "t", "text": "The mammalian molybdenum enzymes of mARC."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Biol Inorg Chem (2015)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1007/s00775-014-1216-4"}], "href": "https://doi.org/10.1007/s00775-014-1216-4"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "25425164"}], "href": "https://pubmed.ncbi.nlm.nih.gov/25425164"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Sudharsan Parthasarathy, Adriana Altuve, Simon Terzyan, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Accommodating a nonconservative internal mutation by water-mediated hydrogen bonding between β-sheet strands: a comparison of human and rat type B (mitochondrial) cytochrome b5."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Biochemistry (2011)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1021/bi2004729"}], "href": "https://doi.org/10.1021/bi2004729"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "21574570"}], "href": "https://pubmed.ncbi.nlm.nih.gov/21574570"}]}, {"type": "r", "ref": 5, "children": [{"type": "t", "text": "Evgeny Yablokov, Anna Florinskaya, Alexei Medvedev, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Thermodynamics of interactions between mammalian cytochromes P450 and b5."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Arch Biochem Biophys (2017)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.abb.2017.02.006"}], "href": "https://doi.org/10.1016/j.abb.2017.02.006"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "28238672"}], "href": "https://pubmed.ncbi.nlm.nih.gov/28238672"}]}, {"type": "r", "ref": 6, "children": [{"type": "t", "text": "Derek Murphy, Jeremy Parker, Minglong Zhou, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Constitutively overexpressed 21 kDa protein in Hodgkin lymphoma and aggressive non-Hodgkin lymphomas identified as cytochrome B5b (CYB5B)."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Cancer (2010)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1186/1476-4598-9-14"}], "href": "https://doi.org/10.1186/1476-4598-9-14"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "20100355"}], "href": "https://pubmed.ncbi.nlm.nih.gov/20100355"}]}, {"type": "r", "ref": 7, "children": [{"type": "t", "text": "M J Billen, E J Squires "}, {"type": "b", "children": [{"type": "t", "text": "The role of porcine cytochrome b5A and cytochrome b5B in the regulation of cytochrome P45017A1 activities."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Steroid Biochem Mol Biol (2009)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.jsbmb.2008.11.012"}], "href": "https://doi.org/10.1016/j.jsbmb.2008.11.012"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "19101629"}], "href": "https://pubmed.ncbi.nlm.nih.gov/19101629"}]}, {"type": "r", "ref": 8, "children": [{"type": "t", "text": "Jacek Pinski, Shigang Xiong, Qingcai Wang, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Effect of luteinizing hormone on the steroidogenic pathway in prostate cancer."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Prostate (2011)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1002/pros.21305"}], "href": "https://doi.org/10.1002/pros.21305"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "21456071"}], "href": "https://pubmed.ncbi.nlm.nih.gov/21456071"}]}, {"type": "r", "ref": 9, "children": [{"type": "t", "text": "Ellen C Kammula, Jessica Mötter, Alexandra Gorgels, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Brain transcriptome-wide screen for HIV-1 Nef protein interaction partners reveals various membrane-associated proteins."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "PLoS One (2012)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1371/journal.pone.0051578"}], "href": "https://doi.org/10.1371/journal.pone.0051578"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "23284715"}], "href": "https://pubmed.ncbi.nlm.nih.gov/23284715"}]}, {"type": "r", "ref": 10, "children": [{"type": "t", "text": "Yawei Ru, Liang Yin, Haidan Sun, et al. "}, {"type": "b", "children": [{"type": "t", "text": "A micropreparation of mitochondria from cells using magnetic beads with immunoaffinity."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Anal Biochem (2012)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.ab.2011.11.015"}], "href": "https://doi.org/10.1016/j.ab.2011.11.015"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "22178913"}], "href": "https://pubmed.ncbi.nlm.nih.gov/22178913"}]}]}]}
Synonyms	CYB5-M, OMB5, CYPB5M
Proteins	CYB5B_HUMAN
NCBI Gene ID	80777
API
Download Associations
Predicted Functions
Co-expressed Genes
Expression in Tissues and Cell Lines

Functional Associations

CYB5B has 8,269 functional associations with biological entities spanning 9 categories (molecular profile, organism, functional term, phrase or reference, chemical, disease, phenotype or trait, structural feature, cell line, cell type or tissue, gene, protein or microRNA, sequence feature) extracted from 121 datasets.

Click the + buttons to view associations for CYB5B from the datasets below.

If available, associations are ranked by standardized value

Harmonizome 3.0

CYB5B Gene

Functional Associations

Please acknowledge the Harmonizome in your publications by citing the following reference(s):

	Dataset	Summary
	Allen Brain Atlas Adult Human Brain Tissue Gene Expression Profiles	tissues with high or low expression of CYB5B gene relative to other tissues from the Allen Brain Atlas Adult Human Brain Tissue Gene Expression Profiles dataset.
	Allen Brain Atlas Adult Mouse Brain Tissue Gene Expression Profiles	tissues with high or low expression of CYB5B gene relative to other tissues from the Allen Brain Atlas Adult Mouse Brain Tissue Gene Expression Profiles dataset.
	Allen Brain Atlas Aging Dementia and Traumatic Brain Injury Tissue Sample Gene Expression Profiles	tissue samples with high or low expression of CYB5B gene relative to other tissue samples from the Allen Brain Atlas Aging Dementia and Traumatic Brain Injury Tissue Sample Gene Expression Profiles dataset.
	Allen Brain Atlas Developing Human Brain Tissue Gene Expression Profiles by Microarray	tissue samples with high or low expression of CYB5B gene relative to other tissue samples from the Allen Brain Atlas Developing Human Brain Tissue Gene Expression Profiles by Microarray dataset.
	Allen Brain Atlas Developing Human Brain Tissue Gene Expression Profiles by RNA-seq	tissue samples with high or low expression of CYB5B gene relative to other tissue samples from the Allen Brain Atlas Developing Human Brain Tissue Gene Expression Profiles by RNA-seq dataset.
	Allen Brain Atlas Prenatal Human Brain Tissue Gene Expression Profiles	tissues with high or low expression of CYB5B gene relative to other tissues from the Allen Brain Atlas Prenatal Human Brain Tissue Gene Expression Profiles dataset.
	BioGPS Cell Line Gene Expression Profiles	cell lines with high or low expression of CYB5B gene relative to other cell lines from the BioGPS Cell Line Gene Expression Profiles dataset.
	BioGPS Human Cell Type and Tissue Gene Expression Profiles	cell types and tissues with high or low expression of CYB5B gene relative to other cell types and tissues from the BioGPS Human Cell Type and Tissue Gene Expression Profiles dataset.
	BioGPS Mouse Cell Type and Tissue Gene Expression Profiles	cell types and tissues with high or low expression of CYB5B gene relative to other cell types and tissues from the BioGPS Mouse Cell Type and Tissue Gene Expression Profiles dataset.
	CCLE Cell Line Gene CNV Profiles	cell lines with high or low copy number of CYB5B gene relative to other cell lines from the CCLE Cell Line Gene CNV Profiles dataset.
	CCLE Cell Line Gene Expression Profiles	cell lines with high or low expression of CYB5B gene relative to other cell lines from the CCLE Cell Line Gene Expression Profiles dataset.
	CCLE Cell Line Proteomics	Cell lines associated with CYB5B protein from the CCLE Cell Line Proteomics dataset.
	CellMarker Gene-Cell Type Associations	cell types associated with CYB5B gene from the CellMarker Gene-Cell Type Associations dataset.
	ChEA Transcription Factor Binding Site Profiles	transcription factor binding site profiles with transcription factor binding evidence at the promoter of CYB5B gene from the CHEA Transcription Factor Binding Site Profiles dataset.
	ChEA Transcription Factor Targets	transcription factors binding the promoter of CYB5B gene in low- or high-throughput transcription factor functional studies from the CHEA Transcription Factor Targets dataset.
	ChEA Transcription Factor Targets 2022	transcription factors binding the promoter of CYB5B gene in low- or high-throughput transcription factor functional studies from the CHEA Transcription Factor Targets 2022 dataset.
	CM4AI U2OS Cell Map Protein Localization Assemblies	assemblies containing CYB5B protein from integrated AP-MS and IF data from the CM4AI U2OS Cell Map Protein Localization Assemblies dataset.
	CMAP Signatures of Differentially Expressed Genes for Small Molecules	small molecule perturbations changing expression of CYB5B gene from the CMAP Signatures of Differentially Expressed Genes for Small Molecules dataset.
	COMPARTMENTS Curated Protein Localization Evidence Scores	cellular components containing CYB5B protein from the COMPARTMENTS Curated Protein Localization Evidence Scores dataset.
	COMPARTMENTS Curated Protein Localization Evidence Scores 2025	cellular components containing CYB5B protein from the COMPARTMENTS Curated Protein Localization Evidence Scores 2025 dataset.
	COMPARTMENTS Experimental Protein Localization Evidence Scores	cellular components containing CYB5B protein in low- or high-throughput protein localization assays from the COMPARTMENTS Experimental Protein Localization Evidence Scores dataset.
	COMPARTMENTS Experimental Protein Localization Evidence Scores 2025	cellular components containing CYB5B protein in low- or high-throughput protein localization assays from the COMPARTMENTS Experimental Protein Localization Evidence Scores 2025 dataset.
	COMPARTMENTS Text-mining Protein Localization Evidence Scores	cellular components co-occuring with CYB5B protein in abstracts of biomedical publications from the COMPARTMENTS Text-mining Protein Localization Evidence Scores dataset.
	COMPARTMENTS Text-mining Protein Localization Evidence Scores 2025	cellular components co-occuring with CYB5B protein in abstracts of biomedical publications from the COMPARTMENTS Text-mining Protein Localization Evidence Scores 2025 dataset.
	COSMIC Cell Line Gene CNV Profiles	cell lines with high or low copy number of CYB5B gene relative to other cell lines from the COSMIC Cell Line Gene CNV Profiles dataset.
	COSMIC Cell Line Gene Mutation Profiles	cell lines with CYB5B gene mutations from the COSMIC Cell Line Gene Mutation Profiles dataset.
	CTD Gene-Chemical Interactions	chemicals interacting with CYB5B gene/protein from the curated CTD Gene-Chemical Interactions dataset.
	CTD Gene-Disease Associations	diseases associated with CYB5B gene/protein from the curated CTD Gene-Disease Associations dataset.
	DeepCoverMOA Drug Mechanisms of Action	small molecule perturbations with high or low expression of CYB5B protein relative to other small molecule perturbations from the DeepCoverMOA Drug Mechanisms of Action dataset.
	DepMap CRISPR Gene Dependency	cell lines with fitness changed by CYB5B gene knockdown relative to other cell lines from the DepMap CRISPR Gene Dependency dataset.
	DISEASES Experimental Gene-Disease Association Evidence Scores 2025	diseases associated with CYB5B gene in GWAS datasets from the DISEASES Experimental Gene-Disease Assocation Evidence Scores 2025 dataset.
	DISEASES Text-mining Gene-Disease Association Evidence Scores	diseases co-occuring with CYB5B gene in abstracts of biomedical publications from the DISEASES Text-mining Gene-Disease Assocation Evidence Scores dataset.
	DISEASES Text-mining Gene-Disease Association Evidence Scores 2025	diseases co-occuring with CYB5B gene in abstracts of biomedical publications from the DISEASES Text-mining Gene-Disease Assocation Evidence Scores 2025 dataset.
	DisGeNET Gene-Disease Associations	diseases associated with CYB5B gene in GWAS and other genetic association datasets from the DisGeNET Gene-Disease Associations dataset.
	DisGeNET Gene-Phenotype Associations	phenotypes associated with CYB5B gene in GWAS and other genetic association datasets from the DisGeNET Gene-Phenoptype Associations dataset.
	ENCODE Histone Modification Site Profiles	histone modification site profiles with high histone modification abundance at CYB5B gene from the ENCODE Histone Modification Site Profiles dataset.
	ENCODE Transcription Factor Binding Site Profiles	transcription factor binding site profiles with transcription factor binding evidence at the promoter of CYB5B gene from the ENCODE Transcription Factor Binding Site Profiles dataset.
	ENCODE Transcription Factor Targets	transcription factors binding the promoter of CYB5B gene in ChIP-seq datasets from the ENCODE Transcription Factor Targets dataset.
	ESCAPE Omics Signatures of Genes and Proteins for Stem Cells	PubMedIDs of publications reporting gene signatures containing CYB5B from the ESCAPE Omics Signatures of Genes and Proteins for Stem Cells dataset.
	GDSC Cell Line Gene Expression Profiles	cell lines with high or low expression of CYB5B gene relative to other cell lines from the GDSC Cell Line Gene Expression Profiles dataset.