Major apolipoprotein of chylomicrons is
**Core Concept**
The major apolipoproteins of chylomicrons are crucial for the transport of dietary triglycerides from the intestines to the liver. Chylomicrons are lipoprotein particles that play a vital role in lipid metabolism, and their apolipoproteins facilitate various enzymatic reactions and receptor interactions.
**Why the Correct Answer is Right**
The major apolipoprotein of chylomicrons is **ApoB-48**. ApoB-48 is a truncated form of ApoB-100, which is the main apolipoprotein of low-density lipoproteins (LDL). ApoB-48 is synthesized in the small intestine and serves as the primary protein component of chylomicrons, enabling their recognition and uptake by LDL receptors in the liver. This process is essential for the removal of excess dietary triglycerides from the bloodstream.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is likely incorrect, as ApoA-I is a major apolipoprotein of high-density lipoproteins (HDL), not chylomicrons.
**Option B:** This option is likely incorrect, as ApoE is a secondary apolipoprotein of chylomicrons, but not the major one.
**Option C:** This option is likely incorrect, as ApoC-II is a cofactor for lipoprotein lipase, an enzyme involved in triglyceride hydrolysis, but it is not the major apolipoprotein of chylomicrons.
**Clinical Pearl / High-Yield Fact**
Apolipoprotein B-48 is synthesized in the small intestine and serves as a unique marker for chylomicron metabolism. Elevated levels of ApoB-48 can indicate impaired chylomicron clearance, which may contribute to the development of hypertriglyceridemia.
**Correct Answer:** B. ApoB-48