This family consists of immunoglobulin A1 protease proteins. The immunoglobulin A1 protease cleaves immunoglobulin IgA and is found in pathogenic bacteria such as Neisseria gonorrhoeae [3]. Not all of the members of this family are IgA proteases Swiss:O32555 from E. coli O157:H7 cleaves human coagulation factor V [2] and Swiss:O88093 is a hemoglobin protease from E. coli EB1 [1].

1: Characterization of a hemoglobin protease secreted by the pathogenic Escherichia coli strain EB1. Otto BR, van Dooren SJ, Nuijens JH, Luirink J, Oudega B; J Exp Med 1998;188:1091-1103. PMID:9743528

2: EspP, a novel extracellular serine protease of enterohaemorrhagic Escherichia coli O157:H7 cleaves human coagulation factor V. Brunder W, Schmidt H, Karch H; Mol Microbiol 1997;24:767-778. PMID:9194704

3: Gene structure and extracellular secretion of Neisseria gonorrhoeae IgA protease. Pohlner J, Halter R, Beyreuther K, Meyer TF; Nature 1987;325:458-462. PMID:3027577