28. Classification of Proteins [Part-1] | Based on Functions, Chemical nature (Solubility) & Shape

Summary

This video tutorial covers the classification of proteins into two main categories: by function and chemical nature. Proteins are categorized by their role in the body, including structural, catalytic, transport, hormonal, contractile, storage, genetic, and defense proteins. Additionally, proteins are classified by their chemical composition into simple proteins (globular and fibrous), conjugated proteins (with non-protein groups), and derived proteins (denatured or degraded forms). Examples and detailed characteristics of each type are provided, helping viewers understand protein diversity and their essential biological roles.

Takeaways

• 😀 Proteins are classified based on two main factors: their function and their chemical nature.
• 😀 Functional classification of proteins includes 8 categories: structural, catalytic, transport, hormonal, contractile, storage, genetic, and defense proteins.
• 😀 Structural proteins help maintain the structure of tissues (e.g., keratin in hair and nails, collagen in bones).
• 😀 Catalytic proteins, such as enzymes, accelerate the rate of chemical reactions (e.g., hexokinase, amylase).
• 😀 Transport proteins, like hemoglobin and albumin, help transport substances such as oxygen and carbon dioxide.
• 😀 Hormonal proteins function like hormones in the body (e.g., insulin, growth hormone).
• 😀 Contractile proteins (e.g., actin and myosin) are responsible for muscle contraction and relaxation.
• 😀 Storage proteins, such as albumin and glutalin, store substances like nutrients and minerals.
• 😀 Genetic proteins help in the regulation and maintenance of genetic material (e.g., nucleoproteins).
• 😀 Defense proteins, such as immunoglobulins and snake venom, help defend the body against harmful invaders.
• 😀 Proteins are also classified based on their chemical nature: simple proteins, conjugated proteins, and derived proteins.
• 😀 Simple proteins consist only of amino acids and are further classified into globular and fibrous proteins based on shape.
• 😀 Conjugated proteins contain both amino acids and non-protein components (prosthetic groups), such as nucleic acids, carbohydrates, lipids, and metals.
• 😀 Derived proteins are created from simple or conjugated proteins through processes like denaturation or degradation.
• 😀 Examples of simple proteins include albumins, globulins, and histones, with specific properties like solubility and amino acid composition.
• 😀 Conjugated proteins can have prosthetic groups like nucleic acids, carbohydrates, lipids, metals, or colored compounds (e.g., hemoglobin, cytochromes, and chromoproteins).

Q & A

What are the two main ways proteins are classified?

Proteins are classified in two main ways: based on their function and based on their chemical nature.

What are the eight categories of proteins classified by function?

The eight categories are: structural proteins, catalytic proteins, transport proteins, hormonal proteins, contractile proteins, storage proteins, genetic proteins, and defense proteins.

What is the primary function of structural proteins?

Structural proteins help in the maintenance of the structure of various tissues in the body. Examples include keratin (important in hair and nails) and collagen (important in bones).

What distinguishes catalytic proteins from other types of proteins?

Catalytic proteins, such as enzymes, accelerate the rate of chemical reactions. Examples include hexokinase and amylase.

How do transport proteins function in the body?

Transport proteins help in the movement of various substances within the body. Hemoglobin, for example, transports oxygen and carbon dioxide, while albumin can transport bilirubin, calcium, and fatty acids.

What role do hormonal proteins play, and can you give examples?

Hormonal proteins act as hormones to regulate bodily functions. Insulin, which helps regulate blood glucose levels, and growth hormone, which stimulates tissue growth, are both examples.

What are contractile proteins, and where are they found?

Contractile proteins are responsible for muscle contraction and relaxation. Key examples are actin and myosin, which are involved in muscle function.

How are conjugated proteins different from simple proteins?

Conjugated proteins contain both amino acids and a non-protein moiety known as a prosthetic group. Unlike simple proteins, which are composed only of amino acids, conjugated proteins are functional only when the prosthetic group is attached.

What are derived proteins, and how are they formed?

Derived proteins are produced by the denaturation or degradation of simple or conjugated proteins. Denaturation involves the breakdown of weak interactions, while degradation involves the hydrolysis of peptide bonds.

What is the significance of the term 'epoprotein' in protein classification?

'Epoprotein' refers to the simple protein component of a conjugated protein, which is not functional by itself but becomes functional when combined with a prosthetic group to form a conjugated protein.