Editing ATP synthase (section)

{{short description|Enzyme}}
{{Infobox enzyme
| Name = ATP Synthase
| EC_number = 7.1.2.2
| CAS_number= 9000-83-3
| GO_code = 0046961
| image = Atp synthase.PNG
| width = 250
| caption = Molecular model of ATP synthase determined by [[X-ray crystallography]]. Stator is not shown here.
}}

'''ATP synthase''' is an [[enzyme]] that catalyzes the formation of the energy storage molecule [[adenosine triphosphate]] (ATP) using [[adenosine diphosphate]] (ADP) and inorganic [[phosphate]] (P<sub>i</sub>). ATP synthase is a [[molecular machine]]. The overall reaction catalyzed by ATP synthase is:
* ADP + P<sub>i</sub> + 2H<sup>+</sup><sub>out</sub> {{Eqm}} ATP + H<sub>2</sub>O + 2H<sup>+</sup><sub>in</sub>

ATP synthase lies across a cellular membrane and forms an aperture that [[hydron (chemistry)|protons]] can cross from areas of high concentration to areas of low concentration, imparting energy for the synthesis of ATP. This [[electrochemical gradient]] is generated by the [[electron transport chain]] and allows cells to store energy in ATP for later use. In  [[prokaryote|prokaryotic cells]] ATP synthase lies across the [[plasma membrane]], while in  [[eukaryote|eukaryotic cells]] it lies across the [[inner mitochondrial membrane]]. Organisms capable of [[photosynthesis]] also have ATP synthase across the [[thylakoid membrane]], which in [[plants]] is located in the [[chloroplast]] and in [[cyanobacteria]] is located in the [[cytoplasm]].

Eukaryotic ATP synthases are [[F-ATPase]]s (which usually work as ATP synthases instead of ATPases in cellular environments) and running "in reverse" for an [[ATPase]] (ATPase [[Catalysis|catalyze]] the [[decomposition]] of [[Adenosine triphosphate|ATP]] into [[Adenosine diphosphate|ADP]] and a free [[Phosphate|phosphate ion]]). This article deals mainly with this type. An F-ATPase consists of two main subunits, F<sub>O</sub> and F<sub>1</sub>, which has a rotational motor mechanism allowing for ATP production.<ref name="Okuno_2011">{{cite journal | vauthors = Okuno D, Iino R, Noji H | title = Rotation and structure of FoF1-ATP synthase | journal = Journal of Biochemistry | volume = 149 | issue = 6 | pages = 655–664 | date = June 2011 | pmid = 21524994 | doi = 10.1093/jb/mvr049 | doi-access = free }}</ref><ref name="Junge_2015">{{cite journal | vauthors = Junge W, Nelson N | title = ATP synthase | journal = Annual Review of Biochemistry | volume = 84 | pages = 631–657 | date = June 2015 | pmid = 25839341 | doi = 10.1146/annurev-biochem-060614-034124 | doi-access = free }}</ref>