Antimicrobial Peptides and their Mechanism of Action

Antimicrobial peptides (AMPs) are small molecular weight proteins with broad spectrum. antimicrobial activity against bacteria, viruses and fungi. These evolutionarily conserved peptides are usually positively charged and have both a hydrophobic and hydrophilic side that enables the molecule to be soluble in aqueous environments yet also enters lipid-rich membranes. Once in a target microbial membrane, the peptide kills target cells through diverse mechanisms. During the past two decades several AMPs have been isolated from a wide variety of animals, both vertebrates and invertebrates, plants as well as from bacteria and fungi. Most of these peptides are obtained from different sources like macrophages, neutrophils, epithelial cells, haemocytes, fat body etc. These peptides exhibit broad-spectrum activity against a wide range of microorganisms including Gram-positive and Gram-negative bacteria, protozoa, yeast, fungi and viruses. A few peptides have also been found to be cytotoxics to sperm. and tumor cells. In this review we present an overview of the general mechanism of action of antimicrobial peptides and discuss some types of antimicrobial peptides.