An experiment was carried out to determine the Kd (equilibrium dissociation constant) values of two newly developed ligands at the same receptor target. Drug C: Kd = 0.8μM Drug D: Kd = 8nM Based on this information, it could be concluded that at this receptor, Drug C:

Question

BlackTom AI · Accepted Answer

Kd (equilibrium dissociation constant) is inversely related to receptor affinity: a lower Kd means the ligand binds more tightly (higher affinity). Kd is the concentration of ligand at which half of the receptors are occupied, so comparing Kd values directly compares affinities.

Step-by-step reasoning and calculations:
1. Convert both Kd values to the same units (nanomolar, nM) for direct comparison.
   - Drug C: 0.8 μM = 0.8 × 10^–6 M = 800 × 10^–9 M = 800 nM.
   - Drug D: 8 nM (already in nM).
2. Compute the ratio of Drug C Kd to Drug D Kd:
   - Ratio = 800 nM / 8 nM = 100.
   This means Drug C’s Kd is 100 times larger than Drug D’s Kd.
3. Interpret the ratio: because Drug C has a Kd 100-fold higher, it requires a 100-fold greater concentration to occupy 50% of receptors compared with Drug D. Therefore Drug C binds the receptor less tightly (lower affinity).

Why the correct answer is correct:
- Kd directly measures binding affinity at equilibrium. Drug D’s much lower Kd (8 nM) indicates it has much higher affinity for the receptor than Drug C (800 nM). Thus the statement “Drug C has lower affinity than Drug D” is the correct conclusion.

Why the other options are incorrect:
- “Is a more potent agonist than Drug D.” Potency depends on both affinity and intrinsic efficacy; Kd alone does not indicate agonist/antagonist identity or efficacy, so you cannot conclude greater potency or agonism from Kd.
- “Has higher affinity than Drug D.” This contradicts the numeric comparison; Drug C’s Kd is larger, so its affinity is lower.
- “Is a less potent antagonist than Drug D.” Antagonist potency likewise depends on functional assays and mechanism; Kd alone does not establish antagonist potency or even whether the ligand is an antagonist.

Conclusion: Drug C has lower affinity than Drug D, matching the provided correct answer.

An experiment was carried out to determine the Kd (equilibrium dissociation constant) values of two newly developed ligands at the same receptor target. Drug C: Kd = 0.8μM Drug D: Kd = 8nM Based on this information, it could be concluded that at this receptor, Drug C:单项选择题

类似问题

An experiment was carried out to determine the Kd (equilibrium dissociation constant) values of two newly developed ligands at the same receptor target. Drug M: Kd = 85nM Drug P: Kd = 2μM Based on this information, it could be concluded that at this receptor, Drug M:

Question at position 8 An excess of growth hormone (GH) before puberty can result in the development ofgigantism.Graves' disease.acromegaly.pituitary dwarfism.Clear my selection

Question at position 6 The most abundant supporting cells in the central nervous system are called Question Blank 1 of 1[input].

Question at position 5 In the eye, the lens functions tofocus light on the retina at the back of the eye.protect the surface of the eye.increase vision in low-light conditions.move the eye side to side.Clear my selection

Question at position 4 Olfactory (odor) receptors are chemoreceptors. TrueFalse

If the pKa of HCHO2 is 3.74 and the pH of an HCHO2/NaCHO2 solution is 3.00, which of the following is TRUE?

Identify the missing particle in the following nuclear equation: 92 236 𝑈 → 38 90 𝑆 𝑟 + ? + 2 0 1 𝑛 + 4 0 0 𝑔

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单