There seems to be a slight mix-up in your question. Cellulase itself is the enzyme that breaks down cellulose. There isn't another enzyme that specifically breaks down cellulase.

Here's why:

* Cellulose: A complex carbohydrate found in the cell walls of plants. It's a major component of plant matter and is difficult to digest for many animals.

* Cellulase: An enzyme that can break down cellulose into simpler sugars that can be absorbed.

However, cellulase can be broken down by proteases. Proteases are enzymes that break down proteins, and cellulase is a protein.

So, while there isn't an enzyme that breaks down cellulase specifically, it can be broken down by enzymes like proteases that are designed to break down proteins.