Answer
They reduce the activation energy required for a reaction, speeding up the reaction. High temperature causes them to break down and they are gradually destroyed. They work best at a certain pH and are destroyed by too low or high pH. They also have a specific shape known as the active site, that is specific to the substrate they speed the reaction of. It means they are specific to one type of reaction. They aren't used in the reaction, so they're re-usable.
Work Step by Step
They reduce the activation energy required for a reaction, speeding up the reaction. High temperature causes them to break down and they are gradually destroyed. They work best at a certain pH and are destroyed by too low or high pH. They also have a specific shape known as the active site, that is specific to the substrate they speed the reaction of. It means they are specific to one type of reaction. They aren't used in the reaction, so they're re-usable.
