Why are zymogens useful in some circumstances?

Zymogen:

1. A zymogen is a proenzyme, that is secreted by several glands present in the body.
2. They display no catalytic activity.
3. It is the inactive form of the enzyme and can be stored or transported safely without any harmful effects on the surrounding tissues.
4. According to the requirements and the optimal conditions, it is converted to the active form and acts on target tissues.
5. For example - pepsin and trypsin are secreted as pepsinogen and trypsinogen, respectively.