Day 8 Flashcards
can be found in almost any cellular proces
protein ligand complexes
mediates the uptake and storage of cargo, such as oxygen uptake in myoglobin and hemoglobin
protein ligand interaction
provides a measure of the affinity for the ligand L for the protein
association constant (Ka)
higher Ka means what for affinity
higher affinity
reciprocal of Ka
dissociation constant
lower Kd means what for affinity
higher affinity
when ligand conc = Kd, how much of the ligand binding sites are occupied
1/2
which is easier to measure, partial pressure of O2 or O2 conc
partial pressure
partial pressure of oxygen at which half of the binding sites are occupied in the dissociation curve of O2 binding to myoglobin
P50
tetrameric protein with 4 heme groups
hemoglobin
how many heme groups in 1 hemoglobin
4
two conformations of hemoglobin
r state and t state
hemoglobin has a higher affinity for O2, which conformation
r state
more stable when O2 is absent
t state
lower affinity for O2, which conformation of hemoglobin
t state
predominant conformation of deoxyhemoglobin
t state
what kind of binding curve does hemoglobin have for oxygen
hybrid sigmoid curve
binding of a ligand to one site affects the binding properties of another site on the same protein
allosteric protein
binding of a ligand to one site affects the binding properties of another site on the same protein, what kind of binding is this
cooperative binding
how many models are there for cooperative binding
2
all subunits in same conformation, what model of cooperative binding
MWC model=concerted model
ligand binds more tightly to the R state, which model of cooperative binding
MWC model=concerted model
each subunit can be in either conformation, which model
sequential model
equilibrium is altered as additional ligands are bound, progressively favoring the R state, which model
sequential
what two products does hemoglobin carry
H+ and CO2
what isn’t soluble in aqueous solutions
CO2
catalyzes the hydration of CO2 to bicarbonate
carbonic anhydrase
what binding to hemoglobin is inversely related to binding of O2
CO2
describes the effect of pH and [CO2] on the binding and release of O2 by hemoglobin
Bohr effect
structural effects of H+ and CO2 binding to hemoglobin favor what state
t state
what regulates oxygen binding to hemoglobin
2,3 bisphosphoglycerate
single amino acid substitution, beta chains produces a hydrophobic patch
sickle cell anemia
deoxygenated hemoglobin becomes…
insoluble and forms polymers that aggegate
