This heat stable bacteriocin inhibits the growth of closely related Lactobacillus species. It may act as a pore-forming protein, creating a channel in the cell membrane. It kills Lactobacillus helveticus ATCC 15009, but displays no activity towards Listeria species. Active lactobin is composed of two different peptides, one which is lactobin A. Belongs to the bacteriocin class IIB family.