The most important buffer in RBC is
|A||O2 Hb + Na Hemoglobinate|
|B||O2Hb + K Hemoglobinate|
|C||H2CO3 + KHCO3|
|D||H2CO3 + NaHCO3|
Buffer system in Blood: -
1. Bicarbonate buffer system 2. Phosphate buffer system
3. Hemoglobin buffer system 4. Plasma protein buffer system
Hemoglobin as buffering system → since Hb present inside RBC — so buffering system in
a. Buffering, provided by imidazole groups of histidine residues of Hb.
b. With the pH range of 7.0 to 7.8, most of the physiological buffering action of Hb is due to the
imidazole group of amino acids histidine
c. O and deoxyHb both acts as buffer, but deoxy HB is better buffer than oxyHb (O2Hb). It is
clear, that, Hb in any form responsible for buffering. Most abundant cation inside RBC is
K+, hence K+Hemoglobinated is more and more >> than Na+Hemoglobinated.
Hence, DeoxyHb + K. Hemoglobinated better buffer than O2Hb + K. Hemoglobinated
But in our ‘Q’ O2Hb + K Hemoglobinated is answer.