1.3.5 Increasing concentrations of H+(with a decrease of ph)or cO, lower the O, affinity of hemoglobin(H+ and co2 has no effect on O2 affinity of myoglobin). This is called bohr effect, which helps the release of o2 in the capillaries of actively metabolizing tissues 1.3.6 One molecule of 2, 3-diphosphoglycerateBPg binds to the central cavity of one tetramer of hemoglobin, which lowers its O2, affinity. 1.3.7 BPG plays critical roles in the physiological adaptation to the lower po2 available at high altitude 1.3.8 Fetal hemoglobin (HbF) binds BPG less strongly than does hemoglobin a(adult and consequently has a higher oxygen affinity1.3.5 Increasing concentrations of H+ (with a decrease of pH) or CO2 lower the O2 affinity of hemoglobin (H+ and CO2 has no effect on O2 affinity of myoglobin). This is called Bohr effect, which helps the release of O2 in the capillaries of actively metabolizing tissues. 1.3.6 One molecule of 2,3-diphosphoglycerate (BPG) binds to the central cavity of one tetramer of hemoglobin, which lowers its O2 affinity. 1.3.7 BPG plays critical roles in the physiological adaptation to the lower pO2 available at high altitude. 1.3.8 Fetal hemoglobin (HbF) binds BPG less strongly than does hemoglobin A (adult) and consequently has a higher oxygen affinity