Globular Proteins vs. Fibrous Proteins: What's the Difference?

Key Difference

Proteins are the essential biological compounds that human body requires in large quantity, due to their huge molecular mass, they are considered macromolecules for the different functions and synthesis actions in the human body. These proteins comprise of one or more polypeptide chains, although the basic structural unit of protein is an amino acid. For the formation of biological proteins, amino acids get combine through the peptide bonds. The word protein is taken from the Greek word ‘proteos,’ which means ‘first.’ The name shows their requirement in the body for various functions. They are present in the protoplasm of the cell, and are responsible for various functions including transportation of material like oxygen, minerals, metals, etc. and for the mechanical movement in the human body. On the basis of 3D dimensional structures, solubility, they are classified as globular and fibrous proteins. Both the proteins are equally essential for the body. The protein which has a rod-like, thread-like or sheet-like structure with having the quality of being insoluble in water is called fibrous proteins, whereas the protein having irregular amino acid sequence and having the quality of getting soluble in water is called globular protein.

Comparison Chart

Globular Proteins  Fibrous Proteins
Solubility Globular proteins are soluble in water, acids, and bases. Fibrous prteins remain insoluble in water, acids, and bases.
Shape & Dimension Globular proteins have ball-like spherical shapes, which are three-dimensional (3D) in nature. Fibrous proteins have rod-like, thread-like or sheet-like structure.
Intermolecular Forces Weak Strong
Function Globular proteins perform various functions including oxygen transportation in blood, glucose metabolism, oxygen storage in muscles and acting as a catalyst for hundreds of reaction taking place within the body. Fibrous proteins perform dozens of functions; from providing tensile strength, rigidity, elasticity, to providing structural functions like formation of scaffold structures inside cells and membrane structures.
Example Examples of globular proteins are myoglobin, insulin, transferrin, and hemoglobin. Examples of fibrous proteins are collagen, desmin, elastin, and F-actin.
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What are Globular Proteins?

Globular proteins are the water-soluble proteins that have irregular amino acid sequence and have ball-like spherical shapes.  These shapes are three-dimensional (3D) in nature as polypeptide chains are folded in such a way to form them. As they are water soluble, they can get transported to the area of action through dissolving in the blood and other body fluids.  Apart from getting soluble in water, they also have the quality to get soluble in acids and bases.  As compared to the fibrous proteins, they are more complex structures as they are formed with polypeptide chains getting folded and forming the final shape ball-like. One of their reason behind getting dissolved in water and other components is their weak intermolecular force. They perform various functions in the human body including oxygen transport in blood, glucose metabolism, oxygen storage in muscles and acting as catalysts for hundreds of reaction taking place within the body. Some of the best examples of globular proteins are myoglobin, insulin, transferrin, and hemoglobin.

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What are Fibrous Proteins?

Fibrous proteins are the proteins that remain insoluble in water, acids, bases and other such compounds. As compared to the globular proteins, they have stronger intermolecular forces of attraction. Therefore they don’t get dissolve or split easily. They have rod-like, thread-like or sheet-like structure, which makes them less complex regarding the shape.  As the name indicates, most of the fibrous proteins are cross-linked in such a manner that they form fibrous structures.  They are equally important as other proteins, although they have more work to do in the mechanical supporting function of the body. From providing tensile strength, rigidity, elasticity, to providing structural functions like the formation of scaffold structures inside cells and membrane structures, they have to perform dozens of tasks in the human body. Some of the best examples of fibrous proteins are collagen, desmin, elastin, and F-actin.

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Globular Proteins vs. Fibrous Proteins

  • Globular proteins are soluble in water, acids, and bases, whereas fibrous proteins remain insoluble in water and other compounds mentioned above.
  • Globular proteins have ball-like spherical shapes, which are three-dimensional (3D) in nature as they are formed by several folds in the polypeptide chains. On the other hand, fibrous proteins have rod-like, thread-like or sheet-like structure.
  • Globular proteins have weak intermolecular hydrogen bonding while fibrous proteins have stronger intermolecular force among molecules.
  • Globular proteins perform various functions including oxygen transportation in blood, glucose metabolism, oxygen storage in muscles and acting as a catalyst for hundreds of reaction taking place within the body. On the other hand, fibrous proteins perform dozens of functions; from providing tensile strength, rigidity, elasticity, to providing structural functions like formation of scaffold structures inside cells and membrane structures.

Explanatory Video

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