This family represents a small conserved region within catalase enzymes (EC:1.11.1.6). All members also contain the Catalase family, Pfam:PF00199 domain. Catalase decomposes hydrogen peroxide into water and oxygen, serving to protect cells from its toxic effects [1]. This domain carries the immune-responsive amphipathic octa-peptide that is recognised by T cells [2].

1: Mitochondrial catalase and oxidative injury. Bai J, Cederbaum AI; Biol Signals Recept 2001;10:189-199. PMID:11351128

2: Do Th1 or Th2 sequence motifs exist in proteins? Identification of amphipatic immunomodulatory domains in Helicobacter pylori catalase. Guy B, Krell T, Sanchez V, Kennel A, Manin C, Sodoyer R; Immunol Lett. 2005;96:261-275. PMID:15585332