Ligand Binding Flashcards
what does epinephrine bind to
Beta adrenergic receptor
low KD means
high affinity
how does oxygen bind to hemoglobin
interacts with iron in heme and forms an H bond with histidine in globin
name of state of hemoglobin not bound to oxygen
taut (T) state
name of hemoglobin bound to oxygen
relaxed (R) state
x and y axis of hemoglobin affinity graph
x: Partial pressure of oxygen
y: fractional saturation
allosteric effectors of hemoglobin
- oxygen
- Carbon Dioxide
- Protons
- 2-3 BPG
how does CO2 affect hemoglobin
present at high partial pressure in active tissues. High CO2 shifts bicarb reaction towards bicarbonate + protons, this lowers the pH and decreases affinity of oxygen for hemoglobin. CO2 also directly binds to hemoglobin which also lowers the affinity.
what is the Bohr effect
lower pH (more acid) lowers hemoglobin affinity for oxygen and releases more. Down-right shift.
what is 2,3 BPG the product of
breakdown of glucose
effect of 2,3 BPG
binding decreases affinity for oxygen. oxygen released at higher partial pressures.
why would 2,3 BPG be increased
people with pathological conditions such as anemia or chronic hypoxia - increases in responses to partial pressure of oxygen in the air, allowing adaptation at high altitudes.
sickle cell anemia point mutation
amino acid 6 switched from glutamine (charged) to valine (uncharged) – changes folding
what does fetal hemoglobin not bind to
2,3 BPG
what does iron bond with in hemoglobin
4 w/ N of ring, 1 w/ histidine of hemoglobin, 1 w/ oxygen
