Lysins are enzymes that break down the cell wall of bacteria, causing rapid destruction of the target organism. They occur naturally in bacteriophages (viruses that infect bacteria but are harmless to humans), where lysins are produced at the end of the infectious cycle to release new bacteriophage particles. Native lysins are rarely optimal for therapeutic use, so Lysigen engineers its own: highly optimized lysins produced in recombinant, purified form, with no viruses used in the production process.

The cell wall maintains the structural integrity of the bacterium and is essential for its survival. Lysins enzymatically cleave the chemical bonds that hold the cell wall together, leading to wall weakening, membrane extrusion, and rapid cell death by osmotic lysis. Because killing depends on this direct enzymatic attack on an essential, conserved structure, bacteria have little opportunity to adapt, making resistance very difficult to develop.