Catalases are conserved and abundant enzyme found in all domains of life. They protect against oxidative stress and are highly expressed. In the gastric pathogen Helicobacter pylori, KatA levels are estimated to be up to 4-5% of the total protein content. The presence of the enzyme is ubiquitous, it could be detected in the cytoplasm, the periplasm and on the cell surface as well as being readily detected extracellularly. The enzyme is described to use heme as cofactor. KatA is used as biomarker for duodenal ulcer (DU) and also for gastritic cancer (GC).
