The Step That Commits Glucose to Glycolysis is Catalyzed By

Question

The step that commits glucose to glycolysis is catalyzed by:
A) hexokinase.
B) pyruvate kinase
C) phosphofructokinase-1 (PFK-1).
D) glucokinase.
E) phosphofructokinase-2 (PFK-2)

Accepted Answer

The step that commits glucose to the glycolytic pathway is the phosphorylation of glucose to glucose-6-phosphate, which is catalyzed by the enzyme hexokinase in most tissues, or by glucokinase in the liver and pancreas. However, the regulation of the glycolytic pathway is mainly carried out by the enzyme phosphofructokinase-1 (PFK-1), which facilitates the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate, the third step of glycolysis. Therefore, the correct answer is C, phosphofructokinase-1 (PFK-1).