Fluoride inhibits
**Fluoride Inhibition of Enzyme**
**Core Concept**
Fluoride is known to inhibit certain enzymes, particularly those involved in glycolysis and glycolytic pathway enzymes. This inhibition is a result of fluoride's ability to bind to the enzyme's active site, thereby preventing the normal catalytic process.
**Why the Correct Answer is Right**
The correct answer is an enzyme that is inhibited by fluoride. Fluoride's inhibition of this enzyme leads to a decrease in the breakdown of glucose, resulting in an accumulation of glucose-6-phosphate. This is a critical step in the glycolytic pathway, and fluoride's inhibition of this enzyme has significant implications for cellular metabolism. The enzyme in question is enolase, which catalyzes the conversion of 2-phosphoglycerate to enolpyruvate in the glycolytic pathway.
**Why Each Wrong Option is Incorrect**
**Option A:** Glycogen synthase is incorrect because fluoride does not directly inhibit this enzyme. Glycogen synthase is involved in glycogenesis, the process of glycogen synthesis.
**Option B:** Phosphofructokinase is incorrect because fluoride does not directly inhibit this enzyme. Phosphofructokinase is involved in the glycolytic pathway, catalyzing the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate.
**Option C:** Pyruvate kinase is incorrect because fluoride does not directly inhibit this enzyme. Pyruvate kinase is involved in the glycolytic pathway, catalyzing the conversion of phosphoenolpyruvate to pyruvate.
**Clinical Pearl / High-Yield Fact**
Fluoride's inhibition of enolase is a critical step in understanding the effects of fluoride on cellular metabolism. This knowledge is essential for understanding the pathophysiology of fluoride toxicity and the mechanisms by which fluoride affects the glycolytic pathway.
**Correct Answer: D. Enolase**