The amino acid which on decarboxylation gives rise to a product with potent vasodilator propeies is:
**Core Concept**
The question is testing the student's knowledge of amino acid metabolism and the production of biogenic amines, which are involved in various physiological and pathological processes. Decarboxylation is a key reaction that converts amino acids into their corresponding amines.
**Why the Correct Answer is Right**
The correct answer is **Histidine**. Upon decarboxylation, Histidine is converted into Histamine, a biogenic amine with potent vasodilator properties. Histamine is involved in various physiological processes, including vasodilation, smooth muscle contraction, and immune responses. It is also implicated in various pathological conditions, such as allergic reactions and asthma. The enzyme responsible for histidine decarboxylation is Histidine Decarboxylase (HDC).
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because Tryptophan is an amino acid that is converted into Serotonin (5-HT) through a series of reactions, not a direct decarboxylation product with vasodilator properties.
* **Option B:** This option is incorrect because Tyrosine is an amino acid that is converted into Catecholamines (e.g., Dopamine, Norepinephrine, and Epinephrine) through a series of reactions, not a direct decarboxylation product with vasodilator properties.
* **Option D:** This option is incorrect because Glutamate is an amino acid that is converted into Gamma-Aminobutyric Acid (GABA) through a decarboxylation reaction, but it does not have potent vasodilator properties.
**Clinical Pearl / High-Yield Fact**
Histamine is involved in the pathophysiology of allergic reactions, and its release is a key event in the development of allergic symptoms. Histamine receptors are targeted by antihistamines, which are commonly used to treat allergic conditions.
**Correct Answer:** C. Histidine. Histidine