The DP-EP family of proteins, formerly known as DUF1888 have been shown to catalyse a cleavage of an internal peptide bond [1].

1: Characterization of member of DUF1888 protein family, self-cleaving and self-assembling endopeptidase. Osipiuk J, Mulligan R, Bargassa M, Hamilton JE, Cunningham MA, Joachimiak A; J Biol Chem. 2012;287:19452-19461. PMID:22493430