Old, worn out cell parts or harmful invaders
Enzymes catalyze specific reactions. It's theoretically possible for there to be an enzyme to catalyze pretty much any chemical reaction, so asking "what do enzymes break down" is kind of like asking "what doors do keys open."
The enzyme amylase can break down starch to maltose.
It is an enzyme...
There is no enzyme which will break down mud.
peptidase enzyme
The body uses enzymes called amylase to break down starches. This enzyme is structured to break down the starch and no other enzyme can perform this function.
Lipases
Horses break down cellulose by use of enzyme cellulase.
Amylase
Proteases are enzymes which break down proteins. Each enzyme can only break down one substance (they are specific to one substrate). This is because their active site has a specific shape to fit a protein and will not fit a starch molecule.
Amylase
catalase
it is used to break down carbs