Learn about Antimicrobial Peptides (AMPs)

Learn about Antimicrobial Peptides (AMPs)
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What are Antimicrobial Peptides (AMPs)?

Antimicrobial peptides, shorted form AMPs, are a kind of cationic small molecule polypeptide produced by organisms with strong antibacterial effect, and is an important component of the innate immune system of organisms. (Brogden, etc. 2005) AMPs are composed of 20-60 amino acid residues, with strong positively charge.

AMPs are an important part of the innate immune system of different organisms. For instance, intestine tract,respiratory tract, reproductive tract and skin all can produce rich AMPs.


                                  Distribution of AMPs

Until now, there are 3569 AMPs are found from 6 kingdoms. That number is still being updated. (https://aps.unmc.edu/home)

Physicochemical Properties of AMPs

Resistant to Drug Resistance

Antimicrobial peptides act on bacteria, not through specific receptors, but through direct membrane breaking mechanisms to kill bacteria

Good Thermalstability

At a high temperature environment of 100℃, the spatial structure of proteins (including secondary structure and tertiary structure, etc.) will be destroyed and the primary structure (the sequence of amino acid residues, the peptide bonds) will remain intact. Antimicrobial peptide, as a small peptide substance, has a relatively simple molecular structure and mainly relies on specific amino acid residue sequence in the primary structure to exert antibacterial activity.

Good Water Solubility
Most AMPs have good solubility. Their N-terminus is hydrophilic and C-terminus is hydrophobic, which has amphiphilicity. And the ends are all amidated, so the solubility is good.

Resistant to Salt and Heavy Mental

It was found that the activity of some AMPs was not affected by high concentrations salt and heavy metals

Resistant to Protease
Studies have shown that some AMPs have the ability to resist the hydrolysis of trypsin and pepsin

High Activity at low pH

It was found that AMPs have high biological activity at low pH

Functions of AMPs

AMPs are the earliest immunoactive molecules produced by organisms in the long-term evolution process in order to adapt to the environment and survive. They are important mediators of natural immunity and play an extremely important role in host immune defense against pathogen invasion. They are vividly called "natural antibacterial agents". They can:

✦  Stimulate non-specific immunity system

✦  Kill bacteria and inhibit fungus and virus