All of the following are tyrosine derivatives, EXCEPT
**Core Concept**
Tyrosine is a non-essential amino acid that serves as a precursor for various neurotransmitters, hormones, and enzymes. Its derivatives play crucial roles in various physiological processes, including neurotransmission and hormone regulation.
**Why the Correct Answer is Right**
To identify the correct answer, we need to analyze the given options and determine which one is not a tyrosine derivative. Tyrosine is converted into L-DOPA by the enzyme tyrosine hydroxylase, which is then decarboxylated to form dopamine. Dopamine is further converted into norepinephrine, and then into epinephrine (adrenaline) by the enzyme dopamine beta-hydroxylase. Another important derivative of tyrosine is thyroxine (T4), which is produced in the thyroid gland.
**Why Each Wrong Option is Incorrect**
**Option A:**
This option is a tyrosine derivative as it is involved in the synthesis of neurotransmitters and hormones.
**Option B:**
This option is a tyrosine derivative as it is a hormone produced in the thyroid gland.
**Option C:**
This option is a tyrosine derivative as it is involved in the synthesis of neurotransmitters and hormones.
**Clinical Pearl / High-Yield Fact**
Tyrosine is a crucial precursor for various neurotransmitters and hormones, including dopamine, norepinephrine, epinephrine, and thyroxine. Understanding the biosynthesis of these compounds is essential for diagnosing and managing various neurological and endocrine disorders.
**Correct Answer:** D.