Question

9. Direct activity of CO2 is a result of binding to which molecular feature? A) the heme group b) the N-terminal ends of the 4 polypeptide chains c) the central cavity d) the proximal His

Answer 1

ANSWER

Direct activity of CO2 is result of binding to N-terminal ends of the 4 polypeptaide chain,

Carbon dioxide bind to hemoglobin and form a carbaminohemoglobine. This decrease in hemoglobin's affinity for oxygen by the binding of carbon dioxide is known as the Bohr effect.

• Hemoglobin bind to CO2, in a manner inversely related to the binding of oxygen.
• Carbon dioxide bind as a carbamate group to alph-amino group at N-terminal end of each globin chain, forming carbaminohimoglobin .
• The reaction produces H, Contributing to Bohr effect.
• The bond carbametes also form additional salt bridges that help to stabilize T state and promote the release of oxygen.
• When the concentration of CO2 is high, as in peripheral tissues, CO2 bind hemoglobin and the affinity of O2 decreases and causing of release O2.
• Also reverse happens in the lungs, when CO2 concentration is low then release CO2 from Hemoglobin.

Carami noh Hb-Nit-co Hb - Nha 14+ ttt Amino-terminal residue. Carbim-termined residue. The liberated Ht protonate of hietidine residue. V At subunit interfaces I are formed. salt-bridge C- T iv Eit---ŌseŅ= salt bridge These salt pridges tavor the elemed conformation - te vor Og release con tavor release q is then taken up r On which myoglobine.