Understanding Structure for Functional Excellence
Definition of Protein: Proteins are complex, large molecules composed of amino acids that are essential for the structure, function, and regulation of living organisms.
Discovery: The understanding of proteins evolved over time, and the term "protein" was coined by Jöns Jakob Berzelius in the early 19th century.
Literal Meaning: The word "protein" is derived from the Greek word "proteios," meaning "of the first rank" or "in the lead."
Importance of Proteins: Proteins are crucial for the growth, repair, and maintenance of cells. They serve as enzymes, structural components, antibodies, hormones, and transporters in various physiological processes.
Types of Proteins in the Human Body: There are thousands of types of proteins in the human body, broadly classified into simple, complex, enzymatic, and non-enzymatic proteins.
Amino Acids: Amino acids are the building blocks of proteins. They are organic compounds with amino and carboxyl groups. There are 20 different types of amino acids.
Types of Amino Acids Based on Occurrence and Solubility:
- On the basis of occurrence in the human body: essential (must be obtained from diet) and non-essential (synthesized by the body).
- On the basis of solubility, hydrophilic (water-soluble) and hydrophobic (water-insoluble)
Involvement of Amino Acids in Protein Formation: Amino acids are linked together through peptide bonds in a specific sequence during protein synthesis, forming polypeptide chains. The sequence dictates the protein's structure and function.
Peptides, peptones, oligopeptides, and polypeptides:
- Peptide: a short chain of amino acids.
- Oligopeptide: Contains a small number of amino acids.
- Polypeptide: a longer chain of amino acids.
- Peptones are partially digested proteins.
Conjugated Proteins: Conjugated proteins have non-protein components (prosthetic groups) in addition to amino acids. Examples include glycoproteins (protein + carbohydrate) and metalloproteins (protein + metal ion).
Simple, Complex, Enzymatic, and Non-Enzymatic Proteins:
- Simple proteins consist only of amino acids (e.g., albumins).
- Complex proteins contain amino acids and non-protein components (e.g., glycoproteins).
- Enzymatic Proteins: act as enzymes, facilitating biochemical reactions (e.g., catalase).
- Non-enzymatic Proteins: Serve structural or regulatory functions (e.g., collagen).
Fibrous and Globular Proteins:
- Fibrous Proteins: Long, insoluble fibers, providing structural support (e.g., collagen).
- Globular Proteins: Compact, spherical, and water-soluble, with diverse functions (e.g., enzymes).
In summary, proteins are diverse and essential molecules with various structures and functions, playing critical roles in the complexity of living organisms.
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