Electron Transport: Complex IV Flashcards
What does Complex IV do?
Catalyzes 1 electron oxidations of 4 consecutive reduced cytochrome c’s and the concomitant 4 electron reduction of one O2
How many redox centers does Complex IV contain?
4
What are the 4 redox centers of Complex IV?
1) Cytochrome a
2) Cytochrome b
3) Copper-b
4) Copper-A
What is the other name for Complex IV?
Cytrochrome c oxidase
What is the path of electron transfer of Complex IV?
Cyto c to Cu-A to - heme a to heme a3 and Cu-B
Where does the reduction of O2 to two H2O take place?
In Complex IV at cytochrome-a3/Cu-B binuclear complex
How many electrons are required for the reduction of O2 to two H2O?
4 (input almost simultaneously)
How many electrons does the fully reduced Fe+2-Cu+1 complex contribute to its bound O2 as it reaches its fully oxidized state?
3 electrons (fully oxidized state is Fe4+-Cu2+)
Where does the 4th electron required for the reduction of O2 come from (in addition to the three from Fe2+-Cu+1)?
From the covalent crosslink within cytochrome c, facilitating both radical formation and proton donation
Which is the most exergonic step in the electron transport chain?
Complex IV
What is the terminal electron accepter in the electron transport chain? What is it reduced to?
O2; H2O
What are the inhibitors of Complex IV?
CN-
