Peptides are short chains of amino acids linked by peptide bonds. Typically peptides contain less than 50 amino acids. Anything longer would be considered a protein. Peptides play several important roles in the human body:
- Signal transmission - Peptides act as chemical messengers allowing cells to communicate with each other. For example, insulin is a peptide hormone that regulates blood sugar levels.
- Immune defense - Antimicrobial peptides are an essential part of the innate immune system, acting as a first line of defense against pathogens.
- Enzyme regulation - Many enzymes are regulated by specific peptide sequences that act as signals to increase or decrease enzyme activity.
There are two main classes of peptides:
- Linear peptides - A simple linear sequence of amino acids linked by peptide bonds.
- Cyclic peptides - The amino acid chain forms a ring structure without free ends. This makes them more stable.
Some key examples of bioactive peptides include:
- Oxytocin - Plays a role in social bonding, sexual reproduction, and during childbirth.
- Bacitracin - An antimicrobial peptide used as an ointment to prevent skin infections.
- Glutathione - An antioxidant that protects cells from free radicals and toxins.
Peptides have growing use as therapeutic agents with advantages over larger protein biologics:
- Better stability - Easily modified to improve resistance to enzyme degradation.
- High potency - High specificity for biological targets at low concentrations.
- Low toxicity - Generally recognized as safe by the body.
- Oral availability - Some linear peptides can be taken orally.
The peptide field is rapidly evolving with applications in biomedicine, research, cosmetics, and food science. Techniques like phage display and computational modeling facilitate peptide design and optimization. Overall, peptides play critical biochemical roles and have untapped therapeutic potential waiting to be explored!
I hope this overview on peptides was helpful. Let me know if you have any other specific questions!