三磷酸腺苷Adenosine triphosphate

ATP 末端两个磷酸酐键常被称为“高能磷酸键”，但能量并非储存在单个键中，而是来自水解前后的整体自由能差：产物 ADP 和 Pᵢ 电荷排斥减小、共振稳定化增加、水合更充分。标准条件下 ΔG°′ = −30.5 kJ/mol，细胞内实际约为 −50 至 −60 kJ/mol。ATP 通常与 Mg²⁺ 配位存在。

The two terminal phosphoanhydride bonds of ATP are often called high-energy bonds, but the energy is not stored in a single bond; it reflects the overall free-energy difference between ATP and its products, which have less charge repulsion, more resonance stabilisation and better hydration. ΔG°′ is −30.5 kJ/mol, and in cells about −50 to −60 kJ/mol. ATP normally exists complexed with Mg²⁺.

1929 年洛曼以及菲斯克和苏巴罗分别从肌肉中分离出 ATP。1935 年托德团队确定其结构（1948 年完成化学合成）。1941 年李普曼提出 ATP 是细胞的“能量货币”，获 1953 年诺贝尔生理学或医学奖。1961 年米切尔提出化学渗透学说解释 ATP 合成，获 1978 年诺贝尔化学奖；博耶和沃克因阐明 ATP 合酶的旋转催化机制获 1997 年诺贝尔化学奖。

In 1929 Lohmann, and independently Fiske and Subbarow, isolated ATP from muscle. Its structure was established in 1935, and Todd's group synthesised it in 1948. In 1941 Lipmann proposed ATP as the cell's energy currency, earning a share of the 1953 Nobel Prize in Physiology or Medicine. Mitchell's chemiosmotic theory of 1961 explained ATP synthesis and won the 1978 Nobel Prize in Chemistry, and Boyer and Walker shared the 1997 Nobel Prize in Chemistry for the rotary mechanism of ATP synthase.

人体内 ATP 总量只有约 250 g，但每天周转量接近体重，约 50–75 kg。ATP 主要由线粒体氧化磷酸化合成，少量来自糖酵解的底物水平磷酸化；肌肉中的磷酸肌酸可快速补充 ATP。ATP 还是 RNA 合成的原料、蛋白激酶的磷酸供体和细胞外信号分子。

The body holds only about 250 g of ATP but turns over roughly its own weight, about 50–75 kg, each day. ATP is made mainly by oxidative phosphorylation in mitochondria, with a little from substrate-level phosphorylation in glycolysis, and muscle phosphocreatine can top it up rapidly. ATP is also a building block for RNA, the phosphate donor for protein kinases and an extracellular signalling molecule.