There are six catalytic types of protease: aspartic acid, cysteine, glutamic, metallo, serine and threonine.
The aspartase proteases are divided into four families.
- Family A01 (Pepsin family)
- Family A02
- Family A22
- Family Ax1
A fifth family has also been described. This family is derived from the prolactin-induced protein/gross cystic disease fluid protein-15 (PIP/GCDFP15).
Read more about this topic: Aspartic Acid Proteases