600 Histidine proline rich glycoprotein (HPRG) is a plasma protein with a lot of

Question

600 Histidine proline rich glycoprotein (HPRG) is a plasma protein with a lot of histidine residues. An experiment measured the binding of HPRG to immobilized heparin (a glycosaminoglycan) at various pHs in the presence of increasing concentrations of zinc (Zn2)- results are shown in the figure. no Zn() 112nM 178nM 33 1 nM - c. Why does HPRG bind to heparin at low pH and why does the binding decrease as the pH increases? (4 points) 6.0 64 6.8 7.2 pH d. Zn2. binds to HPRG in a pH independent manner. Explain why there is less effect of pH on binding o HPRG to heparin in the presence of Zn2 (3 points)

Explanation / Answer

c) At low pH the HPRG is stable and is very well protonated hence HPRG binds to heparin which has
negative charge. At higher pH it will be become unstable and the protons will dethatch themselves
making HPRG to lose its positive charge and hence the binding decreases as PH increases.

d) At higher pH to aid the binding of HPRG to heparin postively charged like Zn+2 are added as
HPRG will get de-protonated at higher pH. Zn2+ binds to HPRG solely based on its charge,
it is like a carrier passive metal ion that helps in facilitated binding. Hence Zn+2 binds to HPRG
in pH independent manner.
  

Related Questions

Navigate

• Browse (All)
• Browse 6
• Subjects

---

---

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