Sodium fluoride inhibits glycolysis by inhibiting the enzyme
**Core Concept**
Sodium fluoride (NaF) is a glycolytic inhibitor that affects the glycolytic pathway by inhibiting an enzyme crucial for glucose metabolism. This enzyme is a key regulatory point in glycolysis, allowing the cell to control the rate of glucose breakdown.
**Why the Correct Answer is Right**
Sodium fluoride specifically inhibits the enzyme enolase (EC 4.2.1.11), which catalyzes the conversion of 2-phosphoglycerate to enolpyruvate in the glycolytic pathway. This enzyme is a crucial step in the conversion of glucose to pyruvate, and its inhibition by NaF effectively shuts down glycolysis. Enolase is a metalloenzyme that requires magnesium ions (Mg²+) for its activity, and NaF competes with these ions, leading to enzyme inhibition.
**Why Each Wrong Option is Incorrect**
* **Option A:** Phosphofructokinase (PFK) is another regulatory enzyme in glycolysis, but it is not the target of sodium fluoride.
* **Option B:** Hexokinase is an enzyme involved in glucose phosphorylation, but it is not the enzyme inhibited by sodium fluoride.
* **Option C:** Pyruvate kinase is another enzyme in the glycolytic pathway, but it is not the target of sodium fluoride inhibition.
**Clinical Pearl / High-Yield Fact**
Sodium fluoride is used in some dental applications to prevent tooth decay, as it inhibits the production of acid by bacteria in the mouth. However, its use as a glycolytic inhibitor in the laboratory setting is more relevant to understanding its mechanism of action.
**Correct Answer:** A. Enolase.