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<entry dataset="Swiss-Prot" created="2006-12-12" modified="2026-09-02" version="131" xmlns="http://uniprot.org/uniprot">
  <accession>Q3SZT9</accession>
  <name>CYC2_BOVIN</name>
  <protein>
    <recommendedName>
      <fullName>Cytochrome c 2</fullName>
    </recommendedName>
  </protein>
  <gene>
    <name type="primary">CYCT</name>
  </gene>
  <organism>
    <name type="scientific">Bos taurus</name>
    <name type="common">Bovine</name>
    <dbReference type="NCBI Taxonomy" id="9913"/>
    <lineage>
      <taxon>Eukaryota</taxon>
      <taxon>Metazoa</taxon>
      <taxon>Chordata</taxon>
      <taxon>Craniata</taxon>
      <taxon>Vertebrata</taxon>
      <taxon>Euteleostomi</taxon>
      <taxon>Mammalia</taxon>
      <taxon>Eutheria</taxon>
      <taxon>Laurasiatheria</taxon>
      <taxon>Artiodactyla</taxon>
      <taxon>Ruminantia</taxon>
      <taxon>Pecora</taxon>
      <taxon>Bovidae</taxon>
      <taxon>Bovinae</taxon>
      <taxon>Bos</taxon>
    </lineage>
  </organism>
  <reference key="1">
    <citation type="submission" date="2005-08" db="EMBL/GenBank/DDBJ databases">
      <authorList>
        <consortium name="NIH - Mammalian Gene Collection (MGC) project"/>
      </authorList>
    </citation>
    <scope>NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA]</scope>
    <source>
      <strain>Crossbred X Angus</strain>
      <tissue>Liver</tissue>
    </source>
  </reference>
  <comment type="function">
    <text evidence="1">Electron carrier protein. The oxidized form of the cytochrome c heme group can accept an electron from the heme group of the cytochrome c1 subunit of cytochrome reductase. Cytochrome c then transfers this electron to the cytochrome oxidase complex, the final protein carrier in the mitochondrial electron-transport chain (By similarity).</text>
  </comment>
  <comment type="function">
    <text evidence="1">Plays a role in apoptosis. Suppression of the anti-apoptotic members or activation of the pro-apoptotic members of the Bcl-2 family leads to altered mitochondrial membrane permeability resulting in release of cytochrome c into the cytosol. Binding of cytochrome c to Apaf-1 triggers the activation of caspase-9, which then accelerates apoptosis by activating other caspases (By similarity).</text>
  </comment>
  <comment type="subcellular location">
    <subcellularLocation>
      <location evidence="1">Mitochondrion intermembrane space</location>
    </subcellularLocation>
    <text evidence="1">Loosely associated with the inner membrane.</text>
  </comment>
  <comment type="PTM">
    <text evidence="1">Binds 1 heme c group covalently per subunit.</text>
  </comment>
  <comment type="PTM">
    <text evidence="1">Phosphorylation at Tyr-49 and Tyr-98 both reduce by half the turnover in the reaction with cytochrome c oxidase, down-regulating mitochondrial respiration.</text>
  </comment>
  <comment type="similarity">
    <text evidence="3">Belongs to the cytochrome c family.</text>
  </comment>
  <comment type="online information" name="Protein Spotlight">
    <link uri="https://www.proteinspotlight.org/back_issues/076"/>
    <text>Life shuttle - Issue 76 of November 2006</text>
  </comment>
  <dbReference type="EMBL" id="BC102714">
    <property type="protein sequence ID" value="AAI02715.1"/>
    <property type="molecule type" value="mRNA"/>
  </dbReference>
  <dbReference type="RefSeq" id="NP_001071431.1">
    <property type="nucleotide sequence ID" value="NM_001077963.2"/>
  </dbReference>
  <dbReference type="RefSeq" id="XP_059733111.1">
    <property type="nucleotide sequence ID" value="XM_059877128.1"/>
  </dbReference>
  <dbReference type="AlphaFoldDB" id="Q3SZT9"/>
  <dbReference type="SMR" id="Q3SZT9"/>
  <dbReference type="FunCoup" id="Q3SZT9">
    <property type="interactions" value="851"/>
  </dbReference>
  <dbReference type="STRING" id="9913.ENSBTAP00000031831"/>
  <dbReference type="PaxDb" id="9913-ENSBTAP00000031831"/>
  <dbReference type="Ensembl" id="ENSBTAT00000031885.4">
    <property type="protein sequence ID" value="ENSBTAP00000031831.2"/>
    <property type="gene ID" value="ENSBTAG00000039522.3"/>
  </dbReference>
  <dbReference type="Ensembl" id="ENSBTAT00085075220">
    <property type="protein sequence ID" value="ENSBTAP00085026938"/>
    <property type="gene ID" value="ENSBTAG00085003512"/>
  </dbReference>
  <dbReference type="Ensembl" id="ENSBTAT00090006600">
    <property type="protein sequence ID" value="ENSBTAP00090002341"/>
    <property type="gene ID" value="ENSBTAG00090004373"/>
  </dbReference>
  <dbReference type="GeneID" id="781996"/>
  <dbReference type="KEGG" id="bta:781996"/>
  <dbReference type="CTD" id="13067"/>
  <dbReference type="VEuPathDB" id="HostDB:ENSBTAG00000039522"/>
  <dbReference type="eggNOG" id="KOG3453">
    <property type="taxonomic scope" value="Eukaryota"/>
  </dbReference>
  <dbReference type="GeneTree" id="ENSGT00940000157883"/>
  <dbReference type="HOGENOM" id="CLU_060944_3_0_1"/>
  <dbReference type="InParanoid" id="Q3SZT9"/>
  <dbReference type="OMA" id="NKGVIWG"/>
  <dbReference type="OrthoDB" id="449280at2759"/>
  <dbReference type="Proteomes" id="UP000009136">
    <property type="component" value="Chromosome 2"/>
  </dbReference>
  <dbReference type="Bgee" id="ENSBTAG00000039522">
    <property type="expression patterns" value="Expressed in semen and 31 other cell types or tissues"/>
  </dbReference>
  <dbReference type="GO" id="GO:0005758">
    <property type="term" value="C:mitochondrial intermembrane space"/>
    <property type="evidence" value="ECO:0000318"/>
    <property type="project" value="GO_Central"/>
  </dbReference>
  <dbReference type="GO" id="GO:0009055">
    <property type="term" value="F:electron transfer activity"/>
    <property type="evidence" value="ECO:0000318"/>
    <property type="project" value="GO_Central"/>
  </dbReference>
  <dbReference type="GO" id="GO:0020037">
    <property type="term" value="F:heme binding"/>
    <property type="evidence" value="ECO:0000501"/>
    <property type="project" value="Ensembl"/>
  </dbReference>
  <dbReference type="GO" id="GO:0006123">
    <property type="term" value="P:mitochondrial electron transport, cytochrome c to oxygen"/>
    <property type="evidence" value="ECO:0000318"/>
    <property type="project" value="GO_Central"/>
  </dbReference>
  <dbReference type="GO" id="GO:0006122">
    <property type="term" value="P:mitochondrial electron transport, ubiquinol to cytochrome c"/>
    <property type="evidence" value="ECO:0000318"/>
    <property type="project" value="GO_Central"/>
  </dbReference>
  <dbReference type="FunFam" id="1.10.760.10:FF:000008">
    <property type="entry name" value="Cytochrome c"/>
    <property type="match status" value="1"/>
  </dbReference>
  <dbReference type="Gene3D" id="1.10.760.10">
    <property type="entry name" value="Cytochrome c-like domain"/>
    <property type="match status" value="1"/>
  </dbReference>
  <dbReference type="InterPro" id="IPR009056">
    <property type="entry name" value="Cyt_c-like_dom"/>
  </dbReference>
  <dbReference type="InterPro" id="IPR036909">
    <property type="entry name" value="Cyt_c-like_dom_sf"/>
  </dbReference>
  <dbReference type="InterPro" id="IPR002327">
    <property type="entry name" value="Cyt_c_1A/1B"/>
  </dbReference>
  <dbReference type="PANTHER" id="PTHR11961">
    <property type="entry name" value="CYTOCHROME C"/>
    <property type="match status" value="1"/>
  </dbReference>
  <dbReference type="Pfam" id="PF00034">
    <property type="entry name" value="Cytochrom_C"/>
    <property type="match status" value="1"/>
  </dbReference>
  <dbReference type="PRINTS" id="PR00604">
    <property type="entry name" value="CYTCHRMECIAB"/>
  </dbReference>
  <dbReference type="SUPFAM" id="SSF46626">
    <property type="entry name" value="Cytochrome c"/>
    <property type="match status" value="1"/>
  </dbReference>
  <dbReference type="PROSITE" id="PS51007">
    <property type="entry name" value="CYTC"/>
    <property type="match status" value="1"/>
  </dbReference>
  <proteinExistence type="inferred from homology"/>
  <keyword id="KW-0053">Apoptosis</keyword>
  <keyword id="KW-0249">Electron transport</keyword>
  <keyword id="KW-0349">Heme</keyword>
  <keyword id="KW-0408">Iron</keyword>
  <keyword id="KW-0479">Metal-binding</keyword>
  <keyword id="KW-0496">Mitochondrion</keyword>
  <keyword id="KW-0597">Phosphoprotein</keyword>
  <keyword id="KW-1185">Reference proteome</keyword>
  <keyword id="KW-0679">Respiratory chain</keyword>
  <keyword id="KW-0813">Transport</keyword>
  <feature type="chain" id="PRO_0000266018" description="Cytochrome c 2">
    <location>
      <begin position="1"/>
      <end position="105"/>
    </location>
  </feature>
  <feature type="binding site" description="covalent" evidence="2">
    <location>
      <position position="15"/>
    </location>
    <ligand>
      <name>heme c</name>
      <dbReference type="ChEBI" id="CHEBI:61717"/>
    </ligand>
  </feature>
  <feature type="binding site" description="covalent" evidence="2">
    <location>
      <position position="18"/>
    </location>
    <ligand>
      <name>heme c</name>
      <dbReference type="ChEBI" id="CHEBI:61717"/>
    </ligand>
  </feature>
  <feature type="binding site" description="axial binding residue" evidence="2">
    <location>
      <position position="19"/>
    </location>
    <ligand>
      <name>heme c</name>
      <dbReference type="ChEBI" id="CHEBI:61717"/>
    </ligand>
    <ligandPart>
      <name>Fe</name>
      <dbReference type="ChEBI" id="CHEBI:18248"/>
    </ligandPart>
  </feature>
  <feature type="binding site" description="axial binding residue" evidence="2">
    <location>
      <position position="81"/>
    </location>
    <ligand>
      <name>heme c</name>
      <dbReference type="ChEBI" id="CHEBI:61717"/>
    </ligand>
    <ligandPart>
      <name>Fe</name>
      <dbReference type="ChEBI" id="CHEBI:18248"/>
    </ligandPart>
  </feature>
  <evidence type="ECO:0000250" key="1"/>
  <evidence type="ECO:0000255" key="2">
    <source>
      <dbReference type="PROSITE-ProRule" id="PRU00433"/>
    </source>
  </evidence>
  <evidence type="ECO:0000305" key="3"/>
  <sequence length="105" mass="11740" checksum="9E5AA14E7AAE7F39" modified="2007-01-23" version="3">MADAEAGKKIFIQKCAQCHTVEKGGKHKTGPNLWGLFGRKTGQAPGFSYTEANKNKGIIWGEQTLMEYLENPKKYIPGTKMIFAGLKKKSEREDLIEYLKQATSS</sequence>
</entry>
<copyright>
Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms Distributed under the Creative Commons Attribution (CC BY 4.0) License
</copyright>
</uniprot>