Differentiate between Hemoglobin and Myoglobin

Hemoglobin and myoglobin are heme proteins that act as oxygen binding proteins. The main point of difference between the two lies in the fact that hemoglobin is found all over the body, and myoglobin is found only in muscle tissues.

Let us take an overview of Hemoglobin and Myoglobin before moving on to their differences.

What is Hemoglobin?

Hemoglobin is a globular protein found in the RBCs, which are responsible for the transport of oxygen from the lungs to the entire body. It is a tetrameric protein made up of two alpha and two beta subunits. Each of the four chains is associated with an iron or heme group which binds with one oxygen molecule each.

What is Myoglobin?

Myoglobin is a globular protein found in the muscles which is responsible for the storage of oxygen in the muscle cells. This stored oxygen is later used up by us while doing different activities. It is a monomeric protein made of a single type of subunit. It has a higher binding affinity than hemoglobin towards oxygen because myoglobin tends to keep oxygen in an oxidation state of +3, which stabilizes it.

Hemoglobin vs Myoglobin

Hemoglobin

Myoglobin

Function
It carries oxygen from the lungs to the rest of the body. It stores oxygen in the muscle cells, which can be utilised as energy.
Structure
Heterotetramer Monomer
Quaternary structure Tertiary structure
Made up of four polypeptide chains – two alpha and two beta Made up of a single polypeptide chain
Protein Type
It is a storage protein It is a transport protein
Type of Curve
It shows a sigmoid curve in a graph of oxygen dissociation. It shows a hyperbolic curve in a graph of oxygen dissociation.
Affinity towards oxygen
Comparatively lower affinity to oxygen, can bind to CO2, CO and NO as well Higher affinity towards oxygen
Molecular weight
64kDa 16.7kDa
Location
Present all over the body Present only in heart and muscle cells
Abbreviation
Hb Mb
Concentration in Blood
Higher concentration in blood Higher concentration in muscles

Keep exploring BYJU’S Biology to learn more in detail about hemoglobin and myoglobin.

Frequently Asked Questions

What are the similarities and differences between myoglobin and hemoglobin?

  • Both are globular proteins
  • Ligand for both myoglobin and hemoglobin is oxygen
  • Both hemoglobin and myoglobin give red colour to muscles and blood.

What are the structural differences between myoglobin and hemoglobin?

Hemoglobin has a quaternary structure composed of two alpha and two beta subunits, whereas myoglobin has a tertiary structure.

What are the functions of hemoglobin and myoglobin?

Hemoglobin functions as an oxygen carrier from the lungs to the entire body and myoglobin functions as a storer of oxygen in the muscle cells.

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