Cytochrome c oxidase

The enzyme cytochrome c oxidase (PDB 2OCC, EC 1.9.3.1) is a large transmembrane protein complex found in bacteria and the mitochondrion. It is the terminal electron acceptor in the electron transport chain. It recieves an electron from each of four cytochrome c molecules, converting molecular oxygen to two molecules of water. In the process, it translocates four protons, helping to establish a chemiosmotic potential that the ATP synthase then uses to synthesize ATP. Image File history File links Gen w/ Deepview from PDB:2OCC File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Gen w/ Deepview from PDB:2OCC File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... The Protein Data Bank (PDB) is a repository for 3-D structural data of proteins and nucleic acids. ... The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... A transmembrane protein is a protein that spans the entire biological membrane. ... Kingdoms Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Electron micrograph of a mitochondrion showing its mitochondrial matrix and membranes In cell biology, a mitochondrion (plural mitochondria) (from Greek μιτος or mitos, thread + κουδριον or khondrion, granule) is a membrane-enclosed organelle, found in most eukaryotic cells. ... The Electron Transport Chain. ... Cytochrome c, or cyt c (horse heart: PDB 1HRC) is a small heme protein found loosely associated with the inner membrane of the mitochondrion. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... Electrochemical potential is a thermodynamic measure that reflects energy from entropy and electrostatics and is typically invoked in molecular processes that involve diffusion. ... An ATP synthase (EC 3. ... Adenosine 5-triphosphate (ATP), discovered in 1929 by Karl Lohmann,[1] is a multifunctional nucleotide primarily known in biochemistry as the molecular currency of intracellular energy transfer. ...

Summary reaction:

4 Fe²⁺-cytochrome c + 8 H⁺_in + O₂ → 4 Fe³⁺-cytochrome c + 2 H₂O + 4 H⁺_out

The complex is a large lipoprotein composed of several metal prosthetic sites and 13 protein subunits. In mammals, ten subunits are nuclear in origin and three are synthesized mitochondrially. The complex contains two cytochromes, the a and a₃ cytochromes, and two copper centers, the Cu_A and Cu_B centers. In fact, the cytochrome a₃ and Cu_B are a binuclear center that is the site of oxygen reduction. The mechanism of action of this large complex is still an active research topic. A lipoprotein is a biochemical assembly that contains both proteins and lipids. ... Hot metal work from a blacksmith In chemistry, a metal (Greek: Metallon) is an element that readily forms positive ions (cations) and has metallic bonds. ... Cytochromes are generally membrane-bound proteins that contain heme groups and carry out electron transport or catalyse reductive/oxidative reactions. ... General Name, Symbol, Number copper, Cu, 29 Chemical series transition metals Group, Period, Block 11, 4, d Appearance metallic pinkish red Atomic mass 63. ...

Cyanide, sulfide, azide and carbon monoxide all bind to Cytochrome c Oxidase, thus inhibiting the protein from functioning which results in chemical suffocation of cells. The cyanide ion, CN−. From the top: 1. ... Flash point -82. ... An azide is the N3- anion, the anion of hydrazoic acid or a reactive group in organic chemistry where a carbon substituent is attached as RN3. ... Carbon monoxide, with the chemical formula CO, is a colourless, odourless and tasteless gas. ... Suffocation can mean two things: Suffocation, or Asphyxia, is a medical condition where the body is depraved of oxygen. ...

External links

• The Cytochrome Oxidase home page
• Interactive Molecular model of cytochrome c oxidase (Requires MDL Chime)
• Calculated spatial positions of cytochrome c oxidases in membrane
• Carbon monoxide specifically inhibits cytochrome C oxidase of human mitochondrial respiratory chain