Hemoglobin Function

role of 3,2-DPG

binds in beta gap in deoxyhemoglobin via salt bridges to stabilize and prevent O2 rebinding

respiratory movement

a series of molecular changes stimulated by the binding of O2 or CO2/H+

oxygen dissociation curve

graphic representation of respiratory movement
effects of H+, CO2, temperature, and 2,3-DPG

sigmoid curve

an s-shaped curve that represents the effect of Heme/Heme interactions

hyperbolic curve

shaped like an upside down L that represents the binding characteristics of a monomeric molecule without Heme/Heme interation (myoglobin)

Direct CO2/H+ transport

2 CO2 bind to 4 amino groups
approximately 4 H+ bind histidine residues

Indirect CO2/H+ transport

CO2 is converted to hydrogen ions and excreted
CO2 + H2O → H2CO3 <-> H+ HCO3-

Bohr effect

effect of changes in pH on hemoglobin dissociation curve

right

the hemoglobin curve shifts to the ____ when there is a decreased pH

left

the hemoglobin curve shifts to the ____ when there is a increased pH

right

increased carbon dioxide shifts the curve to the ____

left

decreased CO2 shifts the curve to the ___

right

increased body temperature shift the curve to the ____

left

decreased body temperature shifts the curve to the ____

right

increased 2,3-DPG shifts the curve to the ___

left

decreased 2,3-DPG shifts the curve to the ____

Carboxyhemoglobin

hemoglobin + carbon monoxide
200X affinity - can’t bind oxygen
0.5% normally → 20-30% toxic
cherry red

Methemoglobin

hemoglobin that has been oxidized
can’t bind oxygen
chocolate brown

Sulfhemoglobin

Hemoglobin + sulfur
irreversible and reduces oxygen affinity
Normal 2.2%
> 3-4% toxic
mauve red or lavendar or greenish