Glycolysis Pathway

Step 1 of glycolysis

Phosphorylation of glucose to G6P. A phosphate group is transferred from ATP to a glucose, making glucose-6-phosphate. Mg²⁺ is used as cofactor (irreversible)

What enzyme is used in step 1

hexokinase in extrahepatic tissue, glucokinase in liver

Step 2 of glycosis

Isomerization of G6P to F6P. glucose-6-phosphate is converted into its isomer, fructose-6-phoshate. Reversible

What enzyme is used in step 2

phosphohexose isomerase

Step 3 of glycolysis

Phosphorylation of F6P, regulatory step. a phosphate group is transferred from ATP to fructose-6-phosphate, producing fructose-1,6-biphosphate. Mg²⁺ is used as a cofactor

Enzyme in step 3

phosphofructokinase-1 (PF)

Step 4 of glycolysis

Cleavage of F16BP. fructose-1,6-biphosphate splits to form dihydroxyacetone phosphate and glyceraldehyde-3-phosphate.

Enzyme used in step 4

aldolase

Step 5 of glycolysis

Isomerization. DHAP is converted into G3P (reversible)

Enzyme used in step 5

triose phosphate isomerase

Step 6 of glycolysis

Oxidation and phosphorylation of G3P. G3P is oxidized and phosphorylated to 1,3FBG by G3PDH. P_i is added to phosphorylate G3P

Enzyme in step 6

Glyceraldehyde-3-phosphate dehydrogenase

Step 7 of glycolysis

Substrate level phosphorylation. 1,3-biphosphoglycerate donates one of its phosphate groups to ADP, making a molecule of ATP and turning into 3-phosphoglycerate in the process. Require Mg²⁺. Happens twice per glucose molecule

Enzyme in step 7

phosphoglycerate kinase

Step 8 of glycolysis

Rearrangement. 3-phosphoglycerate is rearranged to become 2-phosphoglycerate, moving P_i from C-3 to C-2 (reversible)

Enzyme in step 8

phosphoglycerate mutase

Step 9

Dehydration. 2-phosphoglycerate loses a molecule of water, becoming phosphoenolpyruvate (reversible).

Enzyme in step 9

enolase

Step 10 of glycolysis

Substrate level phosphrorylation. phosphoenolpyruvate readily donates its phosphate group to ADP, making a second molecule of ATP. This converts it into pyruvate. Requires Mg²⁺. Happens twice per glucose molecule

Enzyme in step 10

pyruvate kinase