Histamine is formed by of histi dine
**Core Concept**
The underlying principle being tested is the biochemical pathway of histamine synthesis. Histamine is a **biogenic amine** involved in various physiological processes, including allergic reactions and gastric acid secretion. It is synthesized from the amino acid **histidine**.
**Why the Correct Answer is Right**
Histamine is formed by the decarboxylation of **histidine**, a reaction catalyzed by the enzyme **histidine decarboxylase**. This enzyme removes a carboxyl group from **histidine**, resulting in the production of histamine. The correct answer choice should reflect this biochemical process.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the biochemical pathway of histamine synthesis.
**Option B:** This option is also incorrect as it does not involve **histidine** or **histidine decarboxylase**.
**Option C:** Similarly, this option is incorrect as it does not accurately represent the decarboxylation of **histidine**.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that **histamine** plays a crucial role in allergic reactions, and its synthesis from **histidine** is a critical step in understanding the pathophysiology of allergic diseases.
**Correct Answer:** D. decarboxylation of histidine