Concept explainers
(a)
Interpretation:
An oxygen-binding curve for a hypothetical two subunit hemoglobin with
Concept introduction:
Hill equation is represented as follows:
Here, Y- fractional saturation
n − a measure of the degree of cooperativity in ligand binding.
P50 − partial pressure of oxygen at which hemoglobin is half saturated.
The Hill plot of log(Y/1-Y) versus log(P50) should be a linear graph with slope of n.
Answer to Problem 14P
Explanation of Solution
The values of
Y | log(Y/(1-Y) | log(Y/(1-Y)-n log (P50) | log (pO2) | pO2 |
0.1 | -0.95424251 | 0.845757491 | 0.469865 | 2.950294 |
0.2 | -0.60205999 | 1.197940009 | 0.665522 | 4.629374 |
0.3 | -0.36797679 | 1.432023215 | 0.795568 | 6.245518 |
0.4 | -0.17609126 | 1.623908741 | 0.902172 | 7.983099 |
0.5 | 0 | 1.8 | 1 | 10 |
0.6 | 0.176091259 | 1.976091259 | 1.097828 | 12.52646 |
0.7 | 0.367976785 | 2.167976785 | 1.204432 | 16.01148 |
0.8 | 0.602059991 | 2.402059991 | 1.334478 | 21.60119 |
0.9 | 0.954242509 | 2.754242509 | 1.530135 | 33.89493 |
(b)
Interpretation:
An oxygen-binding curve for shypothetical two subunit hemoglobin with
Concept introduction:
Concerted model equation is written as follows:
Here, Y − fractional saturation
a − ratio between the substrate concentration and the dissociation constant for a ligand binding to a single site in R state.
L − The ratio of the concentrations of the T and R states with no ligands bound
c − the ratio between the dissociation constant for a ligand binding to a single site in R state and that of T state.
n − number of binding sites
Also, the ratio can be calculated as follows:
Here,
pO2 − partial pressure of oxygen
KR - the dissociation constant for a ligand binding to a single site in R state.
Answer to Problem 14P
Explanation of Solution
When
Likewise, partial pressure of oxygen for several fractional saturation values are calculated and a plot of fractional saturation versus oxygen partial pressure is drawn.
Y | pO2 |
0.1 | 6.55 |
0.3 | 17.09 |
0.5 | 30.15 |
0.7 | 53.21 |
0.9 | 138.91 |
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