A LACTATE OXIDASE SALIVARY PEROXIDASE THIOCYANATE ANTIBACTERIAL ENZYME-SYSTEM

This work describes an antibacterial enzyme system based on the aerobi c conversion of extracellular L-lactic acid to pyruvic acid and hydrog en peroxide using the enzyme L-lactate oxidase (2-hydroxyacid oxidase) . Subsequent production of hypothiocyanate ions by hydrogen peroxide i n the presence of salivary thiocyanate and sialoperoxidase should lead to a rapid and selective inhibition of dental plaque bacteria. This s ystem was tested in glucose cultures of oral bacteria and results show ed inhibition of acid production in the presence of saliva suggesting that the enzyme shows potential for antibacterial activity under the c onditions found in the mouth. The action of lactate oxidase was compat ible with the enzymes found in Zendium (Oral-B) dentrifice and a mixtu re of the two gave cumulative inhibition. A hydrated aluminium oxide g el provided a substratum for concentrating the enzyme and binding it t o salivary bacterial-protein aggregates.