The name of this superfamily has been modified since the most recent official CATH+ release (v4_3_0). At the point of the last release, this superfamily was named:

"
Cytochrome b5-like heme/steroid binding domain
".

Functional Families

Overview of the Structural Clusters (SC) and Functional Families within this CATH Superfamily. Clusters with a representative structure are represented by a filled circle.
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FunFam 2: Cytochrome b5 type B

Please note: GO annotations are assigned to the full protein sequence rather than individual protein domains. Since a given protein can contain multiple domains, it is possible that some of the annotations below come from additional domains that occur in the same protein, but have been classified elsewhere in CATH.

There are 18 GO terms relating to "molecular function"

The search results have been sorted with the annotations that are found most frequently at the top of the list. The results can be filtered by typing text into the search box at the top of the table.
GO Term Annotations Evidence
Protein binding GO:0005515
Interacting selectively and non-covalently with any protein or protein complex (a complex of two or more proteins that may include other nonprotein molecules).
9 O43169 (/IPI) O43169 (/IPI) O43169 (/IPI) O48845 (/IPI) O48845 (/IPI) Q42342 (/IPI) Q42342 (/IPI) Q9FDW8 (/IPI) Q9FDW8 (/IPI)
Zinc ion binding GO:0008270
Interacting selectively and non-covalently with zinc (Zn) ions.
9 Q03529 (/IDA) Q03529 (/IDA) Q03529 (/IDA) Q03529 (/IDA) Q03529 (/IDA) Q03529 (/IDA) Q03529 (/IDA) Q03529 (/IDA) Q03529 (/IDA)
Electron transfer activity GO:0009055
Any molecular entity that serves as an electron acceptor and electron donor in an electron transport chain. An electron transport chain is a process in which a series of electron carriers operate together to transfer electrons from donors to any of several different terminal electron acceptors to generate a transmembrane electrochemical gradient.
9 P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA)
Fatty acid alpha-hydroxylase activity GO:0080132
Catalysis of the conversion of a fatty acid to an alpha-hydroxylated fatty acid. A hydroxyl group is added to the second carbon, counted from the carboxyl end, of a fatty acid chain.
9 Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP)
Cytochrome-c oxidase activity GO:0004129
Catalysis of the reaction: 4 ferrocytochrome c + O2 + 4 H+ = 4 ferricytochrome c + 2 H2O.
3 P00167 (/TAS) P00167 (/TAS) P00167 (/TAS)
Electron transfer activity GO:0009055
Any molecular entity that serves as an electron acceptor and electron donor in an electron transport chain. An electron transport chain is a process in which a series of electron carriers operate together to transfer electrons from donors to any of several different terminal electron acceptors to generate a transmembrane electrochemical gradient.
3 A0A1D8PQP7 (/IMP) A0A1D8PQP7 (/IMP) A0A1D8PQP7 (/IMP)
Enzyme binding GO:0019899
Interacting selectively and non-covalently with any enzyme.
3 P00167 (/IPI) P00167 (/IPI) P00167 (/IPI)
Heme binding GO:0020037
Interacting selectively and non-covalently with heme, any compound of iron complexed in a porphyrin (tetrapyrrole) ring.
3 O43169 (/IDA) O43169 (/IDA) O43169 (/IDA)
Stearoyl-CoA 9-desaturase activity GO:0004768
Catalysis of the reaction: stearoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ = oleoyl-CoA + 2 ferricytochrome b5 + H2O.
2 P56395 (/TAS) P56395 (/TAS)
Electron transfer activity GO:0009055
Any molecular entity that serves as an electron acceptor and electron donor in an electron transport chain. An electron transport chain is a process in which a series of electron carriers operate together to transfer electrons from donors to any of several different terminal electron acceptors to generate a transmembrane electrochemical gradient.
2 O94391 (/ISO) Q9USM6 (/ISO)
Enzyme binding GO:0019899
Interacting selectively and non-covalently with any enzyme.
2 P56395 (/ISO) P56395 (/ISO)
Sphingosine hydroxylase activity GO:0000170
Catalysis of the hydroxylation of sphingolipid long chain bases.
1 C8VUQ4 (/RCA)
Enzyme activator activity GO:0008047
Binds to and increases the activity of an enzyme.
1 P04166 (/IDA)
Enzyme activator activity GO:0008047
Binds to and increases the activity of an enzyme.
1 Q9CQX2 (/ISO)
Electron transfer activity GO:0009055
Any molecular entity that serves as an electron acceptor and electron donor in an electron transport chain. An electron transport chain is a process in which a series of electron carriers operate together to transfer electrons from donors to any of several different terminal electron acceptors to generate a transmembrane electrochemical gradient.
1 Q86L22 (/ISS)
Electron transfer activity GO:0009055
Any molecular entity that serves as an electron acceptor and electron donor in an electron transport chain. An electron transport chain is a process in which a series of electron carriers operate together to transfer electrons from donors to any of several different terminal electron acceptors to generate a transmembrane electrochemical gradient.
1 P00173 (/TAS)
Heme binding GO:0020037
Interacting selectively and non-covalently with heme, any compound of iron complexed in a porphyrin (tetrapyrrole) ring.
1 Q9CQX2 (/ISO)
Electron transporter, transferring electrons within CoQH2-cytochrome c reductase complex activity GO:0045153
Enables the directed movement of electrons within the CoQH2-cytochrome c reductase complex.
1 P04166 (/TAS)

There are 18 GO terms relating to "biological process"

The search results have been sorted with the annotations that are found most frequently at the top of the list. The results can be filtered by typing text into the search box at the top of the table.
GO Term Annotations Evidence
Inositol phosphoceramide metabolic process GO:0006673
The chemical reactions and pathways involving inositol phosphoceramides, any lipid with a phosphodiester bridge between an inositol residue and the ceramide group.
9 Q03529 (/IGI) Q03529 (/IGI) Q03529 (/IGI) Q03529 (/IGI) Q03529 (/IGI) Q03529 (/IGI) Q03529 (/IGI) Q03529 (/IGI) Q03529 (/IGI)
Inositol phosphoceramide metabolic process GO:0006673
The chemical reactions and pathways involving inositol phosphoceramides, any lipid with a phosphodiester bridge between an inositol residue and the ceramide group.
9 Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP)
Sterol biosynthetic process GO:0016126
The chemical reactions and pathways resulting in the formation of sterols, steroids with one or more hydroxyl groups and a hydrocarbon side-chain in the molecule.
9 P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA)
Ceramide biosynthetic process GO:0046513
The chemical reactions and pathways resulting in the formation of ceramides, any N-acylated sphingoid.
9 Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP) Q03529 (/IMP)
Ergosterol biosynthetic process GO:0006696
The chemical reactions and pathways resulting in the formation of ergosterol, (22E)-ergosta-5,7,22-trien-3-beta-ol, a sterol found in ergot, yeast and moulds.
3 A0A1D8PQP7 (/IMP) A0A1D8PQP7 (/IMP) A0A1D8PQP7 (/IMP)
Xenobiotic metabolic process GO:0006805
The chemical reactions and pathways involving a xenobiotic compound, a compound foreign to living organisms. Used of chemical compounds, e.g. a xenobiotic chemical, such as a pesticide.
3 O43169 (/TAS) O43169 (/TAS) O43169 (/TAS)
L-ascorbic acid metabolic process GO:0019852
The chemical reactions and pathways involving L-ascorbic acid, (2R)-2-
3 P00167 (/TAS) P00167 (/TAS) P00167 (/TAS)
Fatty acid metabolic process GO:0006631
The chemical reactions and pathways involving fatty acids, aliphatic monocarboxylic acids liberated from naturally occurring fats and oils by hydrolysis.
2 P56395 (/IC) P56395 (/IC)
Ergosterol biosynthetic process GO:0006696
The chemical reactions and pathways resulting in the formation of ergosterol, (22E)-ergosta-5,7,22-trien-3-beta-ol, a sterol found in ergot, yeast and moulds.
2 O94391 (/ISO) Q9USM6 (/ISO)
Regulation of hemocyte proliferation GO:0035206
Any process that modulates the frequency, rate or extent of hemocyte proliferation. Hemocytes are blood cells associated with a hemocoel (the cavity containing most of the major organs of the arthropod body) which are involved in defense and clotting of hemolymph, but not involved in transport of oxygen. An example of this is found in Drosophila melanogaster.
2 Q9V4N3 (/IMP) Q9V4N3 (/IMP)
Defense response to bacterium GO:0042742
Reactions triggered in response to the presence of a bacterium that act to protect the cell or organism.
2 Q9ZWT2 (/IEP) Q9ZWT2 (/IEP)
Very long-chain fatty acid biosynthetic process GO:0042761
The chemical reactions and pathways resulting in the formation of a fatty acid which has a chain length greater than C22.
2 O48845 (/IPI) O48845 (/IPI)
Alkane biosynthetic process GO:0043447
The chemical reactions and pathways resulting in the formation of an alkane, any acyclic branched or unbranched hydrocarbon having the general formula CnH2n+2.
2 O48845 (/IDA) O48845 (/IDA)
Regulation of hemocyte differentiation GO:0045610
Any process that modulates the frequency, rate or extent of hemocyte differentiation.
2 Q9V4N3 (/IMP) Q9V4N3 (/IMP)
Cellular response to xenobiotic stimulus GO:0071466
Any process that results in a change in state or activity of a cell (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a xenobiotic compound stimulus. Xenobiotic compounds are compounds foreign to living organisms.
2 A8WGS0 (/IDA) Q7T341 (/IDA)
Glycosphingolipid metabolic process GO:0006687
The chemical reactions and pathways involving glycosphingolipids, any compound with residues of sphingoid and at least one monosaccharide.
1 C8VUQ4 (/RCA)
Electron transport chain GO:0022900
A process in which a series of electron carriers operate together to transfer electrons from donors to any of several different terminal electron acceptors to generate a transmembrane electrochemical gradient.
1 Q86L22 (/IC)
Response to cadmium ion GO:0046686
Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a cadmium (Cd) ion stimulus.
1 P00173 (/IEP)

There are 30 GO terms relating to "cellular component"

The search results have been sorted with the annotations that are found most frequently at the top of the list. The results can be filtered by typing text into the search box at the top of the table.
GO Term Annotations Evidence
Endoplasmic reticulum GO:0005783
The irregular network of unit membranes, visible only by electron microscopy, that occurs in the cytoplasm of many eukaryotic cells. The membranes form a complex meshwork of tubular channels, which are often expanded into slitlike cavities called cisternae. The ER takes two forms, rough (or granular), with ribosomes adhering to the outer surface, and smooth (with no ribosomes attached).
19 O94391 (/HDA) P40312 (/HDA) P40312 (/HDA) P40312 (/HDA) P40312 (/HDA) P40312 (/HDA) P40312 (/HDA) P40312 (/HDA) P40312 (/HDA) P40312 (/HDA)
(9 more)
Endoplasmic reticulum membrane GO:0005789
The lipid bilayer surrounding the endoplasmic reticulum.
10 P00173 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA) P40312 (/IDA)
Endoplasmic reticulum GO:0005783
The irregular network of unit membranes, visible only by electron microscopy, that occurs in the cytoplasm of many eukaryotic cells. The membranes form a complex meshwork of tubular channels, which are often expanded into slitlike cavities called cisternae. The ER takes two forms, rough (or granular), with ribosomes adhering to the outer surface, and smooth (with no ribosomes attached).
9 O48845 (/IDA) O48845 (/IDA) P00173 (/IDA) Q382H2 (/IDA) Q382H2 (/IDA) Q42342 (/IDA) Q42342 (/IDA) Q9ZWT2 (/IDA) Q9ZWT2 (/IDA)
Mitochondrion GO:0005739
A semiautonomous, self replicating organelle that occurs in varying numbers, shapes, and sizes in the cytoplasm of virtually all eukaryotic cells. It is notably the site of tissue respiration.
6 M9NEX3 (/HDA) P56395 (/HDA) P56395 (/HDA) Q8IRR0 (/HDA) Q8SY77 (/HDA) Q9CQX2 (/HDA)
Mitochondrial outer membrane GO:0005741
The outer, i.e. cytoplasm-facing, lipid bilayer of the mitochondrial envelope.
6 O43169 (/TAS) O43169 (/TAS) O43169 (/TAS) P00167 (/TAS) P00167 (/TAS) P00167 (/TAS)
Membrane GO:0016020
A lipid bilayer along with all the proteins and protein complexes embedded in it an attached to it.
6 O43169 (/HDA) O43169 (/HDA) O43169 (/HDA) P00167 (/HDA) P00167 (/HDA) P00167 (/HDA)
Membrane GO:0016020
A lipid bilayer along with all the proteins and protein complexes embedded in it an attached to it.
5 P00167 (/IDA) P00167 (/IDA) P00167 (/IDA) Q5A668 (/IDA) Q5A668 (/IDA)
Intracellular membrane-bounded organelle GO:0043231
Organized structure of distinctive morphology and function, bounded by a single or double lipid bilayer membrane and occurring within the cell. Includes the nucleus, mitochondria, plastids, vacuoles, and vesicles. Excludes the plasma membrane.
5 P00167 (/IDA) P00167 (/IDA) P00167 (/IDA) P00173 (/IDA) P04166 (/IDA)
Endoplasmic reticulum membrane GO:0005789
The lipid bilayer surrounding the endoplasmic reticulum.
4 O94391 (/ISO) P56395 (/ISO) P56395 (/ISO) Q9USM6 (/ISO)
Endoplasmic reticulum membrane GO:0005789
The lipid bilayer surrounding the endoplasmic reticulum.
4 Q42342 (/NAS) Q42342 (/NAS) Q9ZWT2 (/NAS) Q9ZWT2 (/NAS)
Mitochondrial outer membrane GO:0005741
The outer, i.e. cytoplasm-facing, lipid bilayer of the mitochondrial envelope.
3 P04166 (/IDA) Q382H2 (/IDA) Q382H2 (/IDA)
Endoplasmic reticulum GO:0005783
The irregular network of unit membranes, visible only by electron microscopy, that occurs in the cytoplasm of many eukaryotic cells. The membranes form a complex meshwork of tubular channels, which are often expanded into slitlike cavities called cisternae. The ER takes two forms, rough (or granular), with ribosomes adhering to the outer surface, and smooth (with no ribosomes attached).
3 P56395 (/ISO) P56395 (/ISO) Q4QHM6 (/ISO)
Cytosol GO:0005829
The part of the cytoplasm that does not contain organelles but which does contain other particulate matter, such as protein complexes.
3 P00167 (/IDA) P00167 (/IDA) P00167 (/IDA)
Intracellular membrane-bounded organelle GO:0043231
Organized structure of distinctive morphology and function, bounded by a single or double lipid bilayer membrane and occurring within the cell. Includes the nucleus, mitochondria, plastids, vacuoles, and vesicles. Excludes the plasma membrane.
3 P56395 (/ISO) P56395 (/ISO) Q9CQX2 (/ISO)
Nuclear envelope GO:0005635
The double lipid bilayer enclosing the nucleus and separating its contents from the rest of the cytoplasm; includes the intermembrane space, a gap of width 20-40 nm (also called the perinuclear space).
2 Q382H2 (/IDA) Q382H2 (/IDA)
Vacuole GO:0005773
A closed structure, found only in eukaryotic cells, that is completely surrounded by unit membrane and contains liquid material. Cells contain one or several vacuoles, that may have different functions from each other. Vacuoles have a diverse array of functions. They can act as a storage organelle for nutrients or waste products, as a degradative compartment, as a cost-effective way of increasing cell size, and as a homeostatic regulator controlling both turgor pressure and pH of the cytosol.
2 Q42342 (/IDA) Q42342 (/IDA)
Vacuolar membrane GO:0005774
The lipid bilayer surrounding the vacuole and separating its contents from the cytoplasm of the cell.
2 Q42342 (/IDA) Q42342 (/IDA)
Cytosol GO:0005829
The part of the cytoplasm that does not contain organelles but which does contain other particulate matter, such as protein complexes.
2 P56395 (/ISO) P56395 (/ISO)
Plasma membrane GO:0005886
The membrane surrounding a cell that separates the cell from its external environment. It consists of a phospholipid bilayer and associated proteins.
2 Q42342 (/IDA) Q42342 (/IDA)
Chloroplast thylakoid membrane GO:0009535
The pigmented membrane of a chloroplast thylakoid. An example of this component is found in Arabidopsis thaliana.
2 Q42342 (/IDA) Q42342 (/IDA)
Chloroplast outer membrane GO:0009707
The outer, i.e. cytoplasm-facing, lipid bilayer of the chloroplast envelope.
2 Q9FDW8 (/IDA) Q9FDW8 (/IDA)
Stromule GO:0010319
Thin filamentous structure extending from the surface of all plastid types examined so far, including chloroplast, proplastid, etioplast, leucoplast, amyloplast, and chromoplast. In general, stromules are more abundant in tissues containing non-green plastids, and in cells containing smaller plastids. The primary function of stromules is still unresolved, although the presence of stromules markedly increases the plastid surface area, potentially increasing transport to and from the cytosol. Other functions of stromules, such as transfer of macromolecules between plastids and starch granule formation in cereal endosperm, may be restricted to particular tissues and cell types.
2 Q9FDW8 (/IDA) Q9FDW8 (/IDA)
Endomembrane system GO:0012505
A collection of membranous structures involved in transport within the cell. The main components of the endomembrane system are endoplasmic reticulum, Golgi bodies, vesicles, cell membrane and nuclear envelope. Members of the endomembrane system pass materials through each other or though the use of vesicles.
2 Q9V4N3 (/HDA) Q9V4N3 (/HDA)
Membrane GO:0016020
A lipid bilayer along with all the proteins and protein complexes embedded in it an attached to it.
2 P56395 (/ISO) P56395 (/ISO)
Ciliary pocket GO:0020016
Invagination of the plasma membrane from which a cilium (also called flagellum) protrudes.
2 Q382H2 (/IDA) Q382H2 (/IDA)
Nuclear envelope GO:0005635
The double lipid bilayer enclosing the nucleus and separating its contents from the rest of the cytoplasm; includes the intermembrane space, a gap of width 20-40 nm (also called the perinuclear space).
1 Q4QHM6 (/ISO)
Mitochondrial outer membrane GO:0005741
The outer, i.e. cytoplasm-facing, lipid bilayer of the mitochondrial envelope.
1 Q9CQX2 (/ISO)
Mitochondrial inner membrane GO:0005743
The inner, i.e. lumen-facing, lipid bilayer of the mitochondrial envelope. It is highly folded to form cristae.
1 Q9CQX2 (/HDA)
Ciliary pocket GO:0020016
Invagination of the plasma membrane from which a cilium (also called flagellum) protrudes.
1 Q4QHM6 (/ISO)
Perinuclear region of cytoplasm GO:0048471
Cytoplasm situated near, or occurring around, the nucleus.
1 Q93315 (/IDA)