A 45-year-old man with type 2 diabetes and hypertriglyceridemia has markedly elevated VLDL and chylomicrons on lipoprotein electrophoresis (type V pattern). Lipoprotein lipase activity measured in post-heparin plasma is negligible. Which apolipoprotein is necessary for the activation of lipoprotein lipase at the capillary endothelium?
- A ApoA-I
- B ApoC-II ✓
- C ApoB-48
- D ApoE
Correct answer: B. ApoC-II
Explanation
ApoC-II is an essential activator of lipoprotein lipase (LPL) on the capillary endothelium. LPL hydrolyzes triglycerides in chylomicrons and VLDL to release free fatty acids for peripheral uptake. Deficiency of either LPL or ApoC-II results in familial hyperchylomicronemia with severe hypertriglyceridemia and recurrent pancreatitis. ApoA-I activates LCAT, ApoB-48 is the structural protein of chylomicrons, and ApoE mediates receptor-mediated clearance of remnants.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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