Fig. (4).

Classification of aspartic peptidases according to the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. Aspartic peptidases (EC 3.4.23.X) are ordered in subgroup 4 (peptidases) of group 3 (hydrolases) (figure on the right side). Overview of the aspartic peptidase clans, families and subfamilies according to the MEROPS Database [19]. The clan (black boxes) contains enzymes that have arisen from a single evolutionary origin of peptidases and represents one or more families (dark grey circles) that show evidence of their evolutionary relationship. The white circles represent two families with unassigned clans. In addition, some families are divided into subfamilies (light grey boxes) since there is evidence of a very ancient divergence within the family.