Haemoglobin vs. Myoglobin

Main Difference
The main difference between haemoglobin and myoglobin is that haemoglobin is a globin protein that transfers oxygen to all parts of the organism’s body while myoglobin is a globin protein that transfers oxygen to muscle cells only.

Difference Between Haemoglobin and Myoglobin

Haemoglobin vs. Myoglobin

Haemoglobin is a globin protein that transfers oxygen from the lungs to all parts of the body while myoglobin is a globin protein that transfers oxygen to the muscle cells only.

Haemoglobin vs. Myoglobin

Haemoglobin has a tetramer structure while myoglobin is a monomer in structure.

Haemoglobin vs. Myoglobin

Haemoglobin is composed of 4 polypeptide chains whereas myoglobin is composed of the single polypeptide chain.

Haemoglobin vs. Myoglobin

Haemoglobin is present in red blood cells while myoglobin is found in muscle

Haemoglobin vs. Myoglobin

Haemoglobin has four haem groups so it can bind four oxygen molecules, but myoglobin has a single haem group so it can bind a single oxygen molecule because haem group is the place of binding of the oxygen

Haemoglobin vs. Myoglobin

Haemoglobinmay bind with O2, CO2, CO, NO, BPH and H+ while myoglobin may bind with O2 only.

Haemoglobin vs. Myoglobin

Haemoglobin has 64 kDa molecular weight whereas myoglobin has a molecular weight of 16.7 kDa.

Haemoglobin vs. Myoglobin

Haemoglobin has a low affinity to bind with oxygen while myoglobin has a high affinity to bind with oxygen.

Haemoglobin vs. Myoglobin

Haemoglobin involves in the transportation of oxygen and carbon dioxide to or from all parts of the body, in the metabolism of erythrocytes and also maintains the pH of blood while myoglobin is found in muscle cells and provide oxygen to them on the requirement and also regulates the body temperature.

Haemoglobinnoun

alternative spelling of hemoglobin

Myoglobinnoun

(protein) A small globular protein, containing a heme group, that carries oxygen to muscles.

Haemoglobinnoun

a hemoprotein composed of globin and heme that gives red blood cells their characteristic color; function primarily to transport oxygen from the lungs to the body tissues;

fish have simpler hemoglobin than mammals

Myoglobinnoun

a hemoprotein that receives oxygen from hemoglobin and stores it in the tissues until needed

Comparison Chart

Haemoglobin	Myoglobin
Haemoglobin is a globin protein that transfers oxygen from the lungs to all parts of the body.	Myoglobin is a globin protein that transfers oxygen to the muscle cells.
Structure
It has a tetramer structure.	It has a monomer structure.
Chain
It is composed of 4 chains of two different types, i.e., alpha and beta, delta, gamma, or epsilon (on the type basis of different types of hemoglobin).	It is composed of the single polypeptide chain.
Location
It is located throughout the body.	It is located in muscle cells.
Ability to Bind
It has the ability to bind with CO2, NO, CO, O2, and H+	It has the ability to bind to O2
Number of Hemes
It has four hemes, one in each of the subunits	There is one heme in myoglobin
Number of Oxygen Molecules
Four oxygen molecules may bind to hemoglobin	Single oxygen molecule binds to myoglobin
Molecular Weight
Its molecular weight is 64 kDa	Its molecular weight is 16.7 kDa
Affinity to Bind with Oxygen
It has low affinity to bind with oxygen	Myoglobin has a high affinity to bind with oxygen
Concentration in Blood
It has a high concentration in red blood cells	It has a low concentration in the blood
Curve
It shows the sigmoid binding curve	It shows the hyperbolic curve
Also Known As
It is also known as Hb	It is also known as Mb
Function
Haemoglobin binds oxygen and is transported to all parts of the body through blood.	Myoglobin transfers oxygen to muscle cells only, which provides help at the starving time of oxygen.

Haemoglobin vs. Myoglobin

Respiration is a fundamental process of life. Almost every organism requires the transportation of oxygen to all the cells of its body for its survival. Haemoglobin and myoglobin are two basic globin proteins in living organisms that binds oxygen and transfer them to the cells. But, there exist a number of differences between them. Haemoglobin transfers oxygen from the lungs to all parts or cells of the body in vertebrates as well as some invertebrates while myoglobin transfers oxygen to muscle cell only. Haemoglobin is composed of 4 polypeptide chains while myoglobin is composed of the single polypeptide chain. Haemoglobin is found in the bloodstream while myoglobin is found in muscle cells.

What is Haemoglobin?

Haemoglobin is a multi-subunit globin protein with a quaternary structure and is made up of four polypeptide chains, two α, and two β subunits. Each alpha chain is made up of 144 residues and each beta chain is made up of 146 residues. The opposites subunits like alpha and beta associate more strongly than similar subunits alpha-alpha or beta-beta. It is an iron-containing metalloprotein. In haemoglobin, each of the four subunits is attached to a non-protein, prosthetic haem group, where oxygen molecule binds. So, it’s mean that haemoglobin can bind four oxygen molecules with four haem groups of each chain. It has low oxygen affinity in its deoxygenated state, but when first oxygen molecule binds to haemoglobin it leads to the change in its structure that makes the binding of other oxygen molecules easier. This process is called an allosteric (through space) interaction/ cooperativity. Haemoglobin is found in excess in red blood cells and give them a red color. It involves in the transportation of oxygen and carbon dioxide to or from all parts of the body. It also involves the metabolism of erythrocytes and also maintains the pH of the blood.

Types

Haemoglobin A1 (Hb-A1).
Haemoglobin A2 (Hb-A2).
Haemoglobin A3 (Hb-A3).
Embryonic haemoglobin.
Glycosylated haemoglobin.
Foetal Haemoglobin (Hb-A1).

What is Myoglobin?

Myoglobin is a monomer globin protein which exhibits secondary structure. It is composed of a single polynucleotide chain which is composed of 153 residues. It has a single heam group attached to its single polypeptide chain. So, a single oxygen molecule may bind to it. But, its binding capacity is higher than that of haemoglobin, so it serves as an oxygen-storing protein which releases during muscle functioning. It is found in muscle cells and provides oxygen to them on the requirement. It helps the body at the starving conditions of oxygen, especially in the anaerobic conditions. It also regulates body temperature. Myoglobin does not have any type.

Conclusion
From the above discussion, it is concluded that haemoglobin is a tetramer composed of four polynucleotide chains and transport oxygen and carbon dioxide to all parts of the body while myoglobin is a monomer composed of single nucleotide chain and transport oxygen to muscle cells only on the requirement.