Name: how equilibrium binding constant affects binding
Uploaded: 2023-04-30T18:28:41.000Z
Duration: 2 min 18 s
Channel: JoVE

在细胞中，蛋白质随机 与其他分子碰撞 如其他蛋白质，核酸 酸和小分子 配体。如果绑定是非特定的，少数非共价相互作用 分子之间的结果 在简短的联想中。如果是特定的配体 与蛋白质结合，它形成了广泛的 非共价相互作用 沿互补面。这样的复合体是 稳定，持久 绑定很长时间 离解之前。实力一 结合相互作用 根据其报告 平衡常数Kb 也称为绑定 或关联常数。Kb可以从 浓度比 配体复合物的合成 超过浓度 未结合的蛋白质和 平衡时发现配体。鉴于其与自由的关系 由于束缚而引起的能量变化，大Kb意味着大 δG降低 表明有很强的亲和力 在蛋白质和配体之间。两个竞争 流程很重要 用于蛋白质-配体结合。一个协会 蛋白质和配体 形成一个复杂的 复合物的解离 进入反应物。关联常数 K on是一个度量 装订数 每秒事件 在蛋白质之间 及其配体。它可以用来计算 配体结合率 到蛋白质 给定浓度。相反，K off是一个 数的量度 解离事件。它可以用来计算 很快，综合体就崩溃了 当联想率 等于解离率 和平衡 到达哪里 产品浓度 反应物保持恒定。因此，在平衡状态下，钾乘积 均衡的 浓度 蛋白质和 配体，等于K off 乘以平衡 专注 蛋白质-配体复合物。重新安排这个 表达式还显示 K与K之比 平衡点处的Kb等于Kb。

<ol>
	<li>Pollard， Thomas D. "简单而翔实的结合测定指南。"细胞分子生物学 21，第 23 期（2010）:4061-4067。</li>
	<li>Hulme、Edward C. 和 Mike A. Trevethick。"平衡时的配体结合测定:验证和解释。"英国药理学杂志 161，第 6 期（2010）:1219-1237。</li>
	<li>Medina-Franco、José L.、Oscar Méndez-Lucio 和 Karina Martinez-Mayorga。"分子建模和化学信息学之间的相互作用，以表征蛋白质-配体和蛋白质-蛋白质相互作用，用于药物发现。"在蛋白质化学和结构生物学进展中，第 96 卷，第 1-37 页。学术出版社，2014 年。</li>
</ol>

平衡结合常数与结合强度

The Equilibrium Binding Constant and Binding Strength

平衡结合常数 (K_b) 用于量化蛋白质-配体相互作用的强度。 当反应达到平衡时，K_b 可按下式计算：

<img alt="Eq1" src="/files/ftp_upload/11513/Equation 1.png" style="text-align: center; max-width: 100%;">

其中 P 和 L 分别是未结合的蛋白质和配体，PL 是蛋白质-配体复合物。

结合常数不仅与配体的量有关，还与蛋白质与配体的结合速率（kon）和解离速率（koff）相关。因此，实验中也可以通过以下比率由于结合配体的量也与配体结合速率相关，因此实验还可以通过使用以下比率检查蛋白质-配体结合 (kon) 和解离 (koff) 的速率来确定 K_b：

<img alt="Eq1" src="/files/ftp_upload/11513/Equation 2.png" style="text-align: center; max-width: 100%;">

因此，有两类结合测定用于确定平衡结合常数——测量平衡浓度的结合测定和测量反应动力学的结合测定。 以防万一，测量时反应必须处于平衡状态。

确定平衡浓度的方法取决于所需的灵敏度和信号检测的便捷性。 因此 由于这些原因，光谱测定法是得到最广泛的应用的方法之一。 在这些实验中，反应产生的反应物或产物在给定波长下的吸光度变化，可通过紫外-可见分光光度计检测到。 或者，反应物或产物可以用荧光探针标记，或者可以含有内在荧光团。 然后，可以根据荧光的变化来测量反应进度。 这些测定是通过改变一种反应物的浓度来进行的，而实验的其余部分保持不变。 然后可以使用各种曲线拟合方法对结果进行绘图和分析。

此外，还使用各种生化和光谱技术研究蛋白质和配体之间的相互作用。 使用 X 射线晶体学和核磁共振波谱进行结构分析有助于通过分子模拟预测蛋白质-配体相互作用。 理论和计算方法，例如蛋白质-配体对接研究，被广泛用于表征小分子配体（包括候选药物）的位置和相互作用。 计算机辅助药物设计是一种快速且低成本的替代方案，可加快传统试错 试验和错误药物测试的步伐。

平衡结合常数（Kb）用于量化蛋白质与配体相互作用的强度。当反应处于平衡状态时，Kb 可按如下方式计算：...

the-equilibrium-binding-constant-and-binding-strength

Education

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Cell Biology

细胞生物学

Unit 1

第一单元

Energy and Catalysis

能量与催化

KEY TERMS AND CONCEPTS

关键术语与概念

平衡结合常数和结合强度

how equilibrium binding constant affects binding

The equilibrium binding constant describes how strongly two molecules bind at equilibrium. It is a useful way to compare binding strength in molecular interactions.

This topic focuses on how binding is measured and what the equilibrium binding constant means. A higher value indicates stronger binding, while a lower value indicates weaker binding. Understanding this constant helps explain how tightly molecules stay together under equilibrium conditions.

The page also connects the binding constant to real binding strength. It shows why this value matters when comparing different molecular pairs. For high school students, it provides a clear link between a chemistry concept and molecular behavior.

How Equilibrium Binding Constant Affects Binding

how-equilibrium-binding-constant-affects-binding

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the equilibrium binding constant and binding strength

The equilibrium binding constant describes how strongly two molecules bind at equilibrium. It is a useful way to compare binding strength in molecular interactions. This topic focuses on how binding is measured and what the equilibrium binding constant means. A higher value indicates stronger binding, while a lower value indicates weaker binding. Understanding this constant helps explain how tightly molecules stay together under equilibrium conditions. The page also connects the binding...

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key terms and concepts

Learn how the equilibrium binding constant reflects binding strength and why higher or lower values matter in molecular interactions at equilibrium.

How Equilibrium Binding Constant Affects Binding | JoVE K12

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

How Equilibrium Binding Constant Affects Binding

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