Phylogenetic Tree

Peptidase family S10

All known carboxypeptidases are either metallo carboxypeptidases or serine carboxypeptidases. The catalytic activity of the serine carboxypeptidases, like that of the trypsin family serine proteases, is provided by a charge relay system involving an aspartic acid residue hydrogen-bonded to a histidine, which is itself hydrogen-bonded to a serine.

--From Wikipedia