Heme Flashcards
what is the chemical structure of heme?
iron in the center
it is bound to 4 nitrogen
leaves 2 empty spaces for other bonds
What is a prosthetic group?
coenzyme that is permanently associated w/ the enzyme and returned to its original form
how is heme facilitated in myoglobin?
one of the free binding site of heme= binds to histidine group
other free binding site= binds to oxygen
how is the quaternary structure of heme held together?
the alpha and beta globins stick together through hydrophobic interactions
these alphabeta subunits stick to the other alpha beta subunit by hydrogen bonds and ionic bonds
what is P50 in terms of the oxygen dissociation curve?
partial pressure of oxygen needed to bind half of the binding sites
how does a lower pH change hemoglobin’s oxygen affinity?
it lower’s its affinity
shifts the curve to the right
how does 2,3-BPG change hemoglobin’s oxygen affinity?
decreases affinity
shifts the curve to the right
how does binding of CO2 change hemoglobin’s oxygen affinity?
lower’s its oxygen affinity
shifts the curve to the right
how does binding of CO to hemoglobin change its oxygen affinity?
causes a shift to the relaxed form increasing its affinity for oxygen
left shift
what characteristic of HbF causes it to have a higher affinity for oxygen?
it has a lower affinity for 2,3-BPG
what is the mutation in sickle cell anemia?
valine replaces glutamate
what is the mutation in HbC disease?
Lysine substitutes glutamate
