含义Meaning
生化标准态取 pH 7、水的活度为 1、[Mg²⁺] 等按约定给定；有 H⁺ 生成的反应在 pH 7 下比化学标准态（pH 0）更有利。
The biochemical standard state fixes pH 7 and water activity 1; reactions releasing H⁺ are more favourable at pH 7 than at the chemical standard (pH 0).
符号说明Symbols
| 符号Symbol | 含义 Meaning | 单位 Unit |
|---|---|---|
| \(\Delta G^{\circ\prime}\) | 生化标准吉布斯自由能变biochemical standard Gibbs energy change | kJ·mol⁻¹ |
| \(\nu_{\mathrm{H^+}}\) | H⁺ 的计量数（生成为正）stoichiometric number of H⁺ (positive if produced) | 1 |
| \(Q'\) | 不含 H⁺ 与 H₂O 的反应商reaction quotient excluding H⁺ and H₂O | 1 |
推导Derivation
对生成 \(\nu\) 个 H⁺ 的反应，\(\Delta G = \Delta G^\circ + RT\ln Q\)，Q 中含 \(a_{\mathrm{H^+}}^{\nu}\)。
For a reaction producing \(\nu\) H⁺, Q contains \(a_{\mathrm{H^+}}^{\nu}\).
把 \(a_{\mathrm{H^+}} = 10^{-7}\) 的贡献并入标准值：\(\Delta G^{\circ\prime} = \Delta G^\circ + \nu RT\ln 10^{-7} = \Delta G^\circ - 39.9\nu\ \mathrm{kJ/mol}\)（25 °C）。
Absorb \(a_{\mathrm{H^+}} = 10^{-7}\) into the standard value: \(\Delta G^{\circ\prime} = \Delta G^\circ - 39.9\nu\) kJ/mol at 25 °C.
水作为溶剂活度取 1，不出现在 Q′ 中。
Water, as solvent, has activity 1 and is omitted.
适用条件与局限Assumptions & limitations
\(\Delta G^{\circ\prime}\) 还依赖离子强度和 [Mg²⁺]（ATP 以 Mg·ATP 形式存在）；表中数值需注明条件。
Also depends on ionic strength and [Mg²⁺]; tabulated values must state conditions.
细胞内实际 \(\Delta G\) 取决于真实浓度，可与 \(\Delta G^{\circ\prime}\) 相差很大。
Actual cellular \(\Delta G\) depends on real concentrations and can differ greatly.