What does phosphofructokinase do?

What does phosphofructokinase do?

• A. It removes a phosphate group from ATP.
• B. It adds a phosphate group to fructose 6-phosphate.
• C. It converts fructose 6-phosphate to fructose 1,6-bisphosphate.
• D. It oxidizes glucose to gluconate.

Answer: (C)

Phosphofructokinase carries out a key regulatory step in glycolysis by transferring a phosphate from ATP to fructose-6-phosphate, producing fructose-1,6-bisphosphate. This step is the major control point of glycolysis and helps push the pathway forward when energy is needed. The reaction specifically adds a phosphate to carbon 1, forming the bisphosphate that is required for subsequent cleavage into triose phosphates. Understanding the other options helps: removing a phosphate from ATP would be the job of an ATPase, not this enzyme. Adding a phosphate to fructose-6-phosphate is close, but the essential product is fructose-1,6-bisphosphate, not just any single phosphorylation. Oxidizing glucose to gluconate is not part of glycolysis at all.

Phosphofructokinase carries out a key regulatory step in glycolysis by transferring a phosphate from ATP to fructose-6-phosphate, producing fructose-1,6-bisphosphate. This step is the major control point of glycolysis and helps push the pathway forward when energy is needed. The reaction specifically adds a phosphate to carbon 1, forming the bisphosphate that is required for subsequent cleavage into triose phosphates.

Understanding the other options helps: removing a phosphate from ATP would be the job of an ATPase, not this enzyme. Adding a phosphate to fructose-6-phosphate is close, but the essential product is fructose-1,6-bisphosphate, not just any single phosphorylation. Oxidizing glucose to gluconate is not part of glycolysis at all.