Scavengase p20: a novel family of bacterial antioxidant enzymes.

A novel antioxidant enzyme designated scavengase p20 was identified in various pathogenic bacteria through database searching for sequences strikingly homologous to a recently discovered Escherichia coli thiol peroxidase p20. The direct biochemical evidence for the existence of scavengase p20 in Haemophilus influenzae, Streptococcus pneumoniae and Helicobacter pylori was provided by protein microsequencing and by in vitro assays for antioxidant activities. Overlapping genes encoding scavengase p20 and superoxide dismutase were recognized in H. pylori and their functional implications are discussed.