**Core Concept**
Pseudocholinesterase, also known as butyrylcholinesterase, is a type of enzyme that hydrolyzes choline esters, primarily involved in the breakdown of certain anesthetics and muscle relaxants. This enzyme plays a crucial role in the metabolism of drugs like succinylcholine, a depolarizing muscle relaxant used in surgical procedures.

**Why the Correct Answer is Right**
Pseudocholinesterase acts on succinylcholine by cleaving the ester bond, thereby terminating its depolarizing action on the neuromuscular junction. This enzyme is primarily produced in the liver and has a relatively short half-life. Deficiency or abnormal variants of pseudocholinesterase can lead to prolonged apnea and muscle weakness following succinylcholine administration.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because pseudocholinesterase does not primarily act on acetylcholine, which is hydrolyzed by acetylcholinesterase.
**Option B:** Incorrect because pseudocholinesterase is not primarily involved in the breakdown of choline itself, but rather choline esters.
**Option C:** Incorrect because pseudocholinesterase does not primarily act on cocaine, which is metabolized by other enzymes.

**Clinical Pearl / High-Yield Fact**
Patients with pseudocholinesterase deficiency may require alternative muscle relaxants or longer observation periods following succinylcholine administration. This condition can be inherited in an autosomal dominant pattern and may be identified through genetic testing.

**Correct Answer:** D.