Hemoglobin and myoglobin are involved in carrying oxygen to different cells and tissues in the body. While myoglobin is specifically concentrated in the muscles and is responsible for supplying oxygen to muscles cells and tissues, hemoglobin has a more generalized role and carries oxygen to different cells all over the body. They differ in terms of compositions and their structural make up but are similar in function.
Oxygen is vital for every living creature. Hemoglobin and myoglobin play a crucial role in sustaining life. They transport oxygen to cells and tissues. In return, they carry back carbon dioxide from used up cells and tissue, export them back into the lungs for expulsion.
Hemoglobin is called a conjugated protein because it has a protein part called globin and a non-protein part called heme. It is made up four polypeptide (multiple peptides) subunits, namely two alpha and two beta subunits respectively. While the alpha subunit has 144 residues, the beta subunit has 146 residues. Hemoglobin is also called a dimer because the alpha and beta subunits have a strong bonding capacity as compared to bonding with the same subunit (like alpha-alpha or beta-beta).
Myoglobin on the other hand has 153 amino acid residues, slightly higher than its hemoglobin counterparts. It has eight distinct and folded alpha helical structures making it more compact and complicated when compared to hemoglobin. It has a unique polar property. The outer residues have a strong affinity towards water and are called polar, hydrophilic or aqueous residues. The inner surfaces of myoglobin do not like water and are therefore called non-polar or hydrophobic residues.
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