HELICOBACTER-PYLORI ENZYMES

Helicobacter pylori exhibits a complex system of enzymes which serve a range of functions, such as colonization, damage of the host epitheli um and provision of essential metabolic substrates. Colonization is fa voured by urease and by the action on mucus and the mucosal barrier ex erted by phospholipases and proteases, although this latter mechanism is controversial. Toxic effects are effected by urease, alcohol dehydr ogenase (ADH), phospholipases and proteolytic enzymes, ADH produces ac etaldehyde that is toxic to the mucosal cells, while phospholipases in duce generation of products such as lysolecithin, which damage the gas tric epithelium. Catalase and sodium dismutase of H. pylori are mainly involved in transforming toxic oxygen metabolites to harmless water: they protect the bacterium from the killing effect of neutrophils.Meta bolic enzymes (for example, phosphatases, ATPases) are essential for t he generation of energy, for synthesis and transport of cell products and for ion fluxes. In addition, they influence cell growth and the ex pression of virulence factors.