A resecarcher is analyzing the kinetics of binding between insulin-like growth f

Question

A resecarcher is analyzing the kinetics of binding between insulin-like growth factor (GF) and IGF receptor (IGFr) on the cell membrane. In this analysis, he incubated cells in the media supplemented with IGF, and the IGF concentration was 500 HM. At equilibrium, he found that 62.5% of IEC associated with IGF. According to the literature, the association constant is 0.75 s. M-1 Questions: (1) Calculate the dissociation constant (2) Calculate the half-time of the system? (3) Calculate percentages of cellular receptors bound with ligands after 10 min from equilibrium state, while all free IGF was washed away at equilibrium state

Explanation / Answer

Given [IGF] = 500 ; [IGF-IGFr] = 62.5% = 0.625 ; Association constant (Ka) = 0.75 /s/M

1) Dissciation constant (Kd) is the reciprocal of Association constant

Hence, Kd = 1/Ka = 1/0.75 = 1.33 sM

2) Half life is when half of the IGF have dissociated from the receptors

Half life = 2 / Kd = 2 / 1.33 = 1.503 /M

3) According to law of mass action, at equilibrium, Ka = Kd

Ka[IGF][IGFr] = Kd[IGF-IGFr]

where [IGF] and [IGFr} are the free molar concentrations of ligand and receptor respectively.

% of bound receptors after 10 minutes after equilibrium = 500 / 0.625*1.33 = 500 / 0.83 = 61.50 %

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.