Which of the following is an example of a phase 1 Xenobiotic reaction? (Repeat)
**Core Concept**
A phase 1 Xenobiotic reaction, also known as a functionalization reaction, involves the addition of a functional group to a xenobiotic compound, typically resulting in the formation of a more polar metabolite. This process is catalyzed by enzymes belonging to the cytochrome P450 family.
**Why the Correct Answer is Right**
The correct answer is an example of a phase 1 reaction because it involves the addition of a hydroxyl (-OH) group to the xenobiotic compound, resulting in the formation of a more water-soluble metabolite. This process is catalyzed by the enzyme CYP2D6, a member of the cytochrome P450 family. The addition of a hydroxyl group to the xenobiotic compound increases its polarity, making it more susceptible to further metabolism and excretion.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it represents a phase 2 reaction, which involves the conjugation of a xenobiotic compound with a molecule such as glucuronic acid or sulfate.
* **Option B:** This option is incorrect because it represents a phase 3 reaction, which involves the efflux of a xenobiotic compound from cells via transport proteins.
* **Option D:** This option is incorrect because it represents a phase 2 reaction, which involves the conjugation of a xenobiotic compound with a molecule such as glutathione.
**Clinical Pearl / High-Yield Fact**
The cytochrome P450 enzymes play a crucial role in the metabolism of many drugs, and genetic variations in these enzymes can affect an individual's response to certain medications. It is essential for clinicians to be aware of these variations and to adjust dosages accordingly.
**Correct Answer:** C.