A 30-year-old female presents with acute pancreatitis. Serum amylase is 900 U/L on day 1. By day 5, amylase normalises but serum lipase remains 600 U/L. What explains this difference in kinetics?
- A Lipase has a longer serum half-life than amylase because it is not filtered by the kidney ✓
- B Lipase is secreted in larger amounts than amylase by acinar cells
- C Lipase is also produced by gastric chief cells, adding a second source
- D Amylase is destroyed faster by circulating protease inhibitors than lipase
Correct answer: A. Lipase has a longer serum half-life than amylase because it is not filtered by the kidney
Explanation
Serum amylase is a small enzyme (MW ~55 kDa) freely filtered by the glomerulus and rapidly cleared, returning to normal within 3–5 days of pancreatitis onset. Lipase (MW ~48 kDa) is partly reabsorbed by renal tubules and has a longer serum half-life, remaining elevated for 7–14 days, making it more useful for delayed presentations. The output volume of the two enzymes is not the reason for kinetic differences. Gastric chief cells do not produce significant lipase relevant to pancreatitis. Circulating protease inhibitors are not the governing mechanism.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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