Achacin is an antibacterial glycoprotein purified from the mucus of the
giant snail, Achatina fulica Ferussac, as a humoral defense factor. We
showed that achacin has L-amino acid oxidase activity and can generate
cytotoxic H2O2; however, the concentration of H2O2 was not sufficient
to kill bacteria. The antibacterial activity of achacin was inhibited by
various H2O2 scavengers. Immunochemical analysis revealed that achacin
was preferentially bound to growth-phase bacteria, accounting for the
important role in growth-phase-dependent antibacterial activity of achacin.
Achacin may act as an important defense molecule against invading bacteria.