At approximately what pH is pancreatic lipase most active?

At approximately what pH is pancreatic lipase most active?

• A. 5.0
• B. 7.0
• C. 2.0
• D. 9.0

Answer: (B)

Pancreatic lipase works best when its environment lets its catalytic residues have the right charges to act on fat molecules. In the small intestine, the pH is around neutral to slightly alkaline because bicarbonate from the pancreas neutralizes stomach acid. This neutral pH around 7 keeps the enzyme’s active site properly ionized and the protein stable, so it can efficiently hydrolyze triglycerides. If the pH is too acidic, the critical residues become protonated and the enzyme activity drops; if it’s too alkaline, the structure and interactions can also be disrupted. So the best activity occurs at about pH 7, the neutral point.

Pancreatic lipase works best when its environment lets its catalytic residues have the right charges to act on fat molecules. In the small intestine, the pH is around neutral to slightly alkaline because bicarbonate from the pancreas neutralizes stomach acid. This neutral pH around 7 keeps the enzyme’s active site properly ionized and the protein stable, so it can efficiently hydrolyze triglycerides. If the pH is too acidic, the critical residues become protonated and the enzyme activity drops; if it’s too alkaline, the structure and interactions can also be disrupted. So the best activity occurs at about pH 7, the neutral point.