B-Carotene, precursor of vitamin A, is oxidatively cleaved by:
**Core Concept**
B-Carotene, a precursor to vitamin A, undergoes oxidative cleavage in the intestinal mucosa. This process involves the action of an enzyme that breaks down the beta-ionone ring of B-Carotene, releasing two molecules of vitamin A (retinal).
**Why the Correct Answer is Right**
The correct enzyme responsible for the oxidative cleavage of B-Carotene is β-carotene 15,15'-monooxygenase, also known as BCMO1. This enzyme catalyzes the removal of the beta-ionone ring, resulting in the formation of two molecules of retinal, which are then converted into retinol (pre-vitamin A) and subsequently into retinoic acid, a critical derivative of vitamin A. The conversion of B-Carotene to vitamin A is essential for maintaining the visual cycle, immune function, and cell growth.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify an enzyme responsible for the oxidative cleavage of B-Carotene.
* **Option B:** This option is incorrect because it does not accurately describe the enzyme involved in the conversion of B-Carotene to vitamin A.
* **Option D:** This option is incorrect because it is not a known enzyme responsible for the oxidative cleavage of B-Carotene.
**Clinical Pearl / High-Yield Fact**
It's essential to note that genetic mutations in the BCMO1 gene can lead to reduced conversion of B-Carotene to vitamin A, resulting in impaired vision and increased risk of certain cancers.
**Correct Answer: C. β-carotene 15,15'-monooxygenase (BCMO1).**