Biosynthesis of Ribosomal Peptides

Biosynthesis of Ribosomal Peptides

• Ribosomal synthesis of peptides proceeds under genetic control from N-terminus to C-terminus using proteinogenic α-amino acids.
• The process involves transcription, translation, and protein synthesis in the nucleus and cytoplasm.

Importance of Peptides and Proteins

• Peptides and proteins play a central role in nearly all physiological processes of living cells.
• They present a remarkable range of biological properties and have crucial roles in physiological mechanisms.

Classification and Examples

• Hormones: chemical communication and coordination, secreted by neuroendocrine cells and released into the bloodstream to stimulate a response in another organ.
• Neuropeptides: hormones secreted and used in the central nervous system.

Amino Acids and Peptide Bond Formation

• Polypeptides are linear polymers of amino acids linked by peptide bonds.
• Amino acid residues are named by the number of amino acids.
• Peptide bond formation involves a dehydration reaction between the amino group of one amino acid and the carboxyl group of another.

Classification of Peptides

• Dipeptide: two amino acids combined.
• Tripeptide: three amino acids combined.
• Tetrapeptide: four amino acids combined.
• Oligopeptide: a few (4-10) amino acids combined.
• Polypeptide: 10-50 amino acids combined.
• Protein: a large polypeptide (> 50 amino acids).

FDA Regulation

• The FDA distinguishes between proteins and peptides based on size, with "chemically synthesized polypeptide" defined as an alpha-amino acid polymer that is less than 100 amino acids in size and made entirely by chemical synthesis.