Answer: Phosphofructokinase-1.
- A Aldolase
- B Phosphoglucose isomerase
- C Phosphofructokinase-1
- D Pyruvate kinase
Correct answer: C. Phosphofructokinase-1
Explanation: Phosphofructokinase-1 (PFK-1) catalyzes the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate. It is the key regulatory enzyme of glycolysis, inhibited by ATP and citrate.
As substrate concentration rises, reaction rate increases steeply at first, then plateaus at Vmax once every enzyme molecule is working at full capacity; Km is the substrate concentration giving half-maximal rate, and a LOWER Km means the enzyme reaches that rate with less substrate (higher affinity).
Concept context
Carbohydrates, proteins, lipids, nucleic acids, and enzyme kinetics. Essential foundation for understanding metabolism.