Lab 2: Hemoglobin

Function of Hemoglobin

Coopoerative binding: as each molecule of oxygen is bound it further facilitates the binding of the next molecule until all four heme sites are occupied by oxygen.

Hemoglobin Saturation

Hemoglobin saturation of 100 percent means that every heme unit in all of the erythrocytes of the body is bound to oxygen. In a helathy individual hemoglobin saturation ranges from 95 to 99 percent

General Principle of the HB-O2 dossciation curve

Hb binds O2 with higher affinity during conditions displayed on the left side of the curve. That means that the lower pO2 is required for half-saturation (decreased P50). That occurs in the cases of lower temperatures, lower concentrations of 2,3, DPG, and higher pH (alkaline conditions).

DPG

the greater the concentration of DPG, the more readily oxygen dissociates from hemoglobin (right shift), despite its partial pressure

pH

A lower more acidic pH promotes oxygen dissociation from hemoglobin (right shift), a higher more basic pH inhibits oxygen dissociation from hemoglobin (left shift)

Temperature

A higher temperature promotes hemoglobin and oxygen to dissociate faster whereas a lower temperature inhibits oxygen dissociation.

Hemoglobin of the fetus

• fetal hemoglobin has a greater affinity for oxygen than maternal hemoglobin

• They have two different subunits (gamma instead of beta) that allow them to have a greater affinity for oxygen

• They bind less DPG