This family of serine peptidases belong to MEROPS peptidase family S13 (D-Ala-D-Ala carboxypeptidase C, clan SE). The active site residues occur in the motif SXXK. D-Ala-D-Ala carboxypeptidase C is involved in the metabolism of cell components. There are three families of serine-type D-Ala-D-Ala peptidase (designated S11, S12 and S13), which are also known as low molecular weight penicillin-binding proteins. Family S13 comprises D-Ala-D-Ala peptidases that have sufficient sequence similarity around their active sites to assume a distant evolutionary relationship to other clan members; members of the S13 family also bind penicillin and have D-amino-peptidase activity.
Jiyao W et al.(2023). "The conserved domain database in 2023.",