Which of the following metabolizes arginine?
**Core Concept**
Arginine is a semi-essential amino acid that plays a crucial role in various physiological processes, including nitric oxide production, protein synthesis, and urea cycle regulation. The metabolism of arginine involves several enzymes and pathways, which are essential for maintaining proper cellular function.
**Why the Correct Answer is Right**
Arginine is primarily metabolized by the enzyme arginase, which catalyzes the conversion of arginine to ornithine and urea. This process is a key step in the urea cycle, where excess nitrogen is removed from the body. Arginase is a mitochondrial enzyme that is found in the liver and kidneys, where it plays a critical role in nitrogen metabolism.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because arginase is the primary enzyme responsible for arginine metabolism, not ornithine transcarbamylase (OTC). OTC is involved in the urea cycle, but it catalyzes a different reaction.
**Option B:** This option is incorrect because aspartate transaminase (AST) is an enzyme involved in amino acid metabolism, but it does not play a direct role in arginine metabolism.
**Option C:** This option is incorrect because glutamate dehydrogenase (GLDH) is an enzyme involved in glutamate metabolism, but it is not directly involved in arginine metabolism.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that arginine metabolism is closely linked to the urea cycle, and disturbances in this pathway can lead to conditions such as hyperammonemia and urea cycle disorders.
**Correct Answer: C. Arginase**