P50 of hemoglobin at pH 7.4 and 20°C

Value 7.1 mmHg
Organism Water buffalo Bubalus bubalis
Reference Giardina B, Arevalo F, Clementi ME, Ferrara L, Di Luccia A, Lendaro E, Bellelli A, Condò SG. Evolution of ruminant hemoglobins. Thermodynamic divergence of ox and buffalo hemoglobins. Eur J Biochem. 1992 Mar 1 204(2):509-13. p.510 left column bottom paragraphPubMed ID1541266
Method "Oxygen dissociation curves were obtained spectrophotometrically by the tonometric method."
Comments "Buffalo Hb are characterized by a very-low O2 affinity, even in the absence of organic phosphates such as GriP2. Under these conditions at pH 7.4 and 20°C (in 0.1 M Hepes plus 0.1 M NaCl), P50 is 7.1 mmHg, a value almost identical to that of human hemoglobin fully saturated with its physiological effector (GriP2)."
Entered by Uri M
ID 109696