Sometimes referenced as 2 to 30 amino acids linked. Protein - a large peptide containing 50 or more amino acid residues. Common Names - The naming of enzymes is a confusing thing. Common names for enzymes are also taken from their substrate, their product and their common uses. With a given field of use, common names often make useful handles for communication purposes.
Common names are, by themselves, uninformative.
Common names for enzymes aren't cast in stone - make up a name if it suits your purpose. Everyone else does. These subclasses can be further dissected. The proteases are listed under EC3.4.x.x. Each volume is 4 to 6 inches thick and updates are sent out regularly.