Chapter 5: Hill Equation & Other Ligands That Hemoglobin Binds

Question 1

Hill Equation

Answer 1

mathematical description of cooperative binding

log (theta/(1-theta)) = nlog[L] - log Kd

y = mx + b

Question 2

what does nsubh stand for?

Answer 2

Hill coefficient

nh = 1 means no cooperativity (MG)

nh > 1 means positive cooperativity

nh < 1 means negative cooperativity

Question 3

positive cooperativity

Answer 3

ligand binding results in easier binding for more ligand

Question 4

negative cooperativity

Answer 4

ligand binding makes it harder for more ligand to bind

Question 5

axes of a Hill plot

Answer 5

y axis = log (theta / (1 - theta))

x axis = log [L]

Question 6

axes of a Hill plot for MG/HG

Answer 6

y axis = log (theta / (1 - theta))

x axis = log [pO2]

Question 7

Hill plot things to know

Answer 7

logarithmic plot so 0 is in the middle of both axes

nh is labeled for different affinity states

Question 8

CO2 binding to HG

Answer 8

binds to the alpha chains giving N-terminus a negative charge

stabilizes the low affinity state via ionic interactions

result is HG las a lower affinity for O2 (in tissues drops off more O2 than usual) and transports CO2 to the lungs

Question 9

Acid binding to HG

Answer 9

H+ stabilizes the low affinity state

release more O2 in tissues

high [H+]/low pH means less binding

Question 10

BPG

Answer 10

(2,3 biphosphoglycerate) binds between subunits

stabilizes low affinity state

can’t bind to the high affinity state

high [BPG] means less binding