Many enzymes have been named by adding the suffix-ase to the name of their substrate.

e.g. Urease catalyzes the hydrolysis of urea

Arginase catalyzes the hydrolysis of arginine.

But many enzymes have been given names that do not denote their substrates

e.g. Pepsin

The same enzyme is known by two or more names or that two different enzymes have been given the same name.