P

Peptide Bond

Peptide bond: -CO-NH-; formed by condensation: -COOH + H₂N- → -CO-NH- + H₂O
Quick Reference
Formula / NotationPeptide bond: -CO-NH-; formed by condensation: -COOH + H₂N- → -CO-NH- + H₂O
Also Known AsAmide bond (in peptide context), peptide linkage, polypeptide bond, −CO−NH−

What is Peptide Bond?

A covalent bond formed between the carboxyl group of one amino acid and the amino group of another, with loss of water. Peptide bonds link amino acids together to form polypeptides and proteins. They have partial double-bond character due to resonance, restricting rotation.

Formula & Notation

Peptide bond: -CO-NH-; formed by condensation: -COOH + H₂N- → -CO-NH- + H₂O

Other Names / Synonyms: Amide bond (in peptide context), peptide linkage, polypeptide bond, −CO−NH−

Properties & Characteristics

A peptide bond is the covalent amide bond (−CO−NH−) formed between the carboxyl group (−COOH) of one amino acid and the amino group (−NH₂) of another, with loss of water (condensation reaction). The peptide bond is planar due to partial double bond character (resonance delocalisation). Peptide bonds link amino acids into polypeptide chains. In proteins, the backbone consists of repeating −N−Cα−C(=O)− units. Hydrolysis of peptide bonds is catalysed by proteases or mineral acids.

Uses & Applications

Peptide bonds form the backbone of all proteins and peptides, which perform virtually all biological functions. Synthetic peptides are used as pharmaceuticals (insulin, oxytocin, GnRH analogues), research tools (cell-penetrating peptides), and in food science (hydrolysed proteins as flavour enhancers). Proteases that cleave peptide bonds are industrial enzymes (meat tenderisers, detergent enzymes).

Safety Information

No direct safety hazard from the peptide bond itself. Proteins containing toxic amino acid sequences (e.g., ricin, which contains a cytotoxic A chain) must be handled appropriately. Hydrolysis of proteins with concentrated HCl at 110°C (amino acid analysis) requires a sealed, pressure-rated vessel and safe acid handling.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Peptide Bond
Formula Peptide bond: -CO-NH-; formed by condensation: -COOH + H₂N- → -CO-NH- + H₂O
Synonyms Amide bond (in peptide context), peptide linkage, polypeptide bond, −CO−NH−

Frequently Asked Questions

A covalent bond formed between the carboxyl group of one amino acid and the amino group of another, with loss of water. Peptide bonds link amino acids together to form polypeptides and proteins. They have partial double-bond character due to resonance, restricting rotation.

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