Editing Adenosine triphosphate (section)

=== Muscle contraction ===
ATP fuels [[muscle contraction]]s.<ref>{{Cite journal |last1=Hultman |first1=E. |last2=Greenhaff |first2=P. L. |date=1991 |title=Skeletal muscle energy metabolism and fatigue during intense exercise in man |url=https://pubmed.ncbi.nlm.nih.gov/1842855/ |journal=Science Progress |volume=75 |issue=298 Pt 3-4 |pages=361–370 |issn=0036-8504 |pmid=1842855}}</ref> Muscle contractions are regulated by signaling pathways, although different [[muscle]] types being regulated by specific pathways and stimuli based on their particular function. However, in all muscle types, contraction is performed by the proteins [[actin]] and [[myosin]].<ref name=":0">{{Cite journal |last1=Kuo |first1=Ivana Y. |last2=Ehrlich |first2=Barbara E. |date=February 2015 |title=Signaling in Muscle Contraction |journal=Cold Spring Harbor Perspectives in Biology |language=en |volume=7 |issue=2 |pages=a006023 |doi=10.1101/cshperspect.a006023 |issn=1943-0264 |pmc=4315934 |pmid=25646377}}</ref>

ATP is initially bound to myosin. When [[ATPase]] hydrolyzes the bound ATP into [[Adenosine diphosphate|ADP]] and inorganic [[phosphate]], myosin is positioned in a way that it can bind to actin. Myosin bound by ADP and P<sub>i</sub> forms cross-bridges with actin and the subsequent release of ADP and P<sub>i</sub> releases energy as the power stroke. The power stroke causes actin filament to slide past the myosin filament, shortening the muscle and causing a contraction. Another ATP molecule can then bind to myosin, releasing it from actin and allowing this process to repeat.<ref name=":0" /><ref>{{Cite web |date=2018-07-16 |title=38.17: Muscle Contraction and Locomotion - ATP and Muscle Contraction |url=https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_General_Biology_(Boundless)/38%3A_The_Musculoskeletal_System/38.17%3A_Muscle_Contraction_and_Locomotion_-_ATP_and_Muscle_Contraction |access-date=2024-05-01 |website=Biology LibreTexts |language=en}}</ref>