Concept:
Digestion involves breakdown of complex food substances into simpler absorbable forms.
Step 1: Understanding fat digestion.
Fats are mainly triglycerides. They must be broken down into fatty acids and glycerol or monoglycerides before absorption.
Step 2: Role of lipase.
Lipase is the enzyme that digests fats. Pancreatic lipase is especially important in the small intestine.
\[
\text{Triglyceride} \xrightarrow{\text{Lipase}} \text{Fatty acids} + \text{Glycerol}
\]
Step 3: Checking other enzymes.
Amylase digests carbohydrates.
Pepsin digests proteins in the stomach.
Trypsin digests proteins in the small intestine.
Lipase digests fats.
Step 4: Final answer.
Therefore, the enzyme involved in digestion of fats is lipase.
\[
\boxed{\text{Lipase}}
\]