In an individual, three distinct proteins bind oxygen depending on the location and development stage. While hemoglobin is the major oxygen binding protein in adults, myoglobin is present in skeletal muscles and fetal hemoglobin is present in fetal stage only. The following graph shows the oxygen binding capacity of these proteins. The A, B and C plots represent oxygen binding capacity of 
To determine which plots A, B, and C correspond to myoglobin, fetal hemoglobin, and hemoglobin, we need to understand the oxygen binding properties of these proteins:
- Myoglobin: Myoglobin has a high affinity for oxygen and binds to it very strongly, even at low oxygen pressures. This characteristic results in a hyperbolic oxygen dissociation curve with a steep initial slope, reaching saturation quickly.
- Fetal Hemoglobin: Fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin. This allows effective transfer of oxygen from the mother to the fetus. The curve for fetal hemoglobin is typically to the left of the adult hemoglobin curve.
- Hemoglobin: Adult hemoglobin shows a sigmoidal dissociation curve due to cooperative binding. This curve is to the right of both myoglobin and fetal hemoglobin.
Analyzing the graph:
- Plot A, which saturates quickly even at low pO2, represents myoglobin.
- Plot B, being to the left of plot C, represents fetal hemoglobin.
- Plot C, with a sigmoidal curve typical of cooperative binding, represents hemoglobin.
Therefore, the plots can be identified as myoglobin, fetal hemoglobin, and hemoglobin, respectively.
The correct answer is: myoglobin, fetal hemoglobin, and hemoglobin, respectively.
Important Questions from Protein Structure Folding Alpha Helix
- A 25 amino acid $\alpha$-helical protein is spanning the thickness of a mammalian cell membrane. Using the average dimensional parameters of a typical $\alpha$-helix, the thickness of the membrane will be ________ $\text{\AA}$ (rounded off to one decimal place).
The following diagram represents energy states of different protein folding steps, which includes-
1. Folded
2. Transition
3. Molten globule
4. Unfolded
Find the correct match of folding steps (1 to 4) with the energy state (P to S) in the diagram.- In a $\alpha$-helix, the R-groups on the amino acid residues
- Which one of the following pairs of amino-acids in the protein has high propensity to take up the $\alpha$-helix conformation?
- Which one of the following closely defines 'Molten Globule' state of a protein?
