This family formerly known as DUF1671 has been shown to be a cysteine peptidase called (Ufm1)-specific protease [1].

1: Two Novel Ubiquitin-fold Modifier 1 (Ufm1)-specific Proteases, UfSP1 and UfSP2. Kang SH, Kim GR, Seong M, Baek SH, Seol JH, Bang OS, Ovaa H, Tatsumi K, Komatsu M, Tanaka K, Chung CH; J Biol Chem. 2007;282:5256-5262. PMID:17182609