Preparatory Phase of Glycolysis

Step 1 of Glycolysis

Glucose → Glucose-6-phosphate

What Enzyme Catalyzes Step 1?

Hexokinase, alongside Mg2+

• Point of Regulation

What are the Products of Step 1?

ADP (ATP → ADP)

Is Step 1 Reversible or Irreversible?

Irreversible

Step 2 of Glycolysis

Glucose-6-phosphate → Fructose-6-phosphate

What Enzyme Catalyzes Step 2?

Phosphohexose Isomerase

Is Step 2 Reversible or Irreversible?

Reversible

Step 3 of Glycolysis

Fructose-6-phosphate → Fructose 1,6-Bisphosphate

What Enzyme Catalyzes Step 3?

Phosphofructose Kinase (PFK)

• Point of regulation

• Committed step

What are the Products of Step 3?

ADP (ATP → ADP)

Is Step 3 Reversible or Irreversible?

Irreversible

Step 4 of Glycolysis

Fructose 1,6-Bisphosphate → Glyceraldehyde 3-phosphate and Dihydroxyacetone Phosphate

• Cleavage between C3 and C4

What Enzyme Catalyzes Step 4?

Fructose 1,6-Bisphosphate Aldolase

Is Step 4 Reversible or Irreversible?

Reversible

Step 5 of Glycolysis

Dihydroxyacetone phosphate → Glyceraldehyde-3-phosphate

What Enzyme Catalyzes Step 5?

Triose Phosphate

Is Step 5 Reversible or Irreversible?

Reversible