Question

3. (20 pts) Given the basic sigmoid oxygen binding curve for hemoglobin, (a) Write out the overall AGⓇ for the binding of the first O2 to hemoglobin in terms of component free energy contributions. H6+0₂ - H602 PG, Роа (b) Expand your equation to include the contribution of the allosteric effector, 2,3-DPG to the standard state free energy change. (c) Write out the chemical equations and the related free energy changes for binding the first oxygen to hemoglobin in the Monod model with c-0).

Answer 1

Model a) Monod Relaxed (R) Taut (T) L = [To]/[ro] » kg = [In] [s]/[T+] KR = [RA] [5] / [en] ka « ps Substrate binding equilibrice changes TR ISS 88:88:88:8=8 c = KR /kr [02] /ke=& TJ S 11s V SIS Ty = a(Ita)n-1 Lealitca)n-1 . (1+2)+L(1 + con

② Basic Sigmoidal curve Haemogloluir - - 0.8 0.6 0.4 P50 = 26 torr 0.2 + o 0.0 100 25 50 75 pO2 (torr) → of first og to Hb: @ Overall Ago equation for for binding barn erall Ago equation Binding of 1st O m Hb + O₂ (aq) - HBO2 :. All - +2.9 kcal/mu (cooperative fuce energy 2D A44 D+Dx 449, AG T (untigated) 1 142 Tax (singly ligated) - Az