10 Steps of Glycolysis

Step 1

Glucose + ATP » Glucose 6-phosphate + ADP

step 1 product

G6P/ADP

Step 1 enzyme

Hexokinase

Step 2

Glucose 6-Phosphate » Fructose 6-phosphate

step 2 product

fructose 6 phosphate

Step 2 enzyme

Phosphoglucose Isomerase

Step 3

Fructose 6-Phosphate + ATP » Fructose 1,6-biphosphate + ADP

step 3 product

fructose-1,6-bisphosphate

Step 3 enzyme

Phosphofructokinase

Step 4

Fructose 1,6-biphosphate » glyceraldehyde 3-phosphate + dihydroxyacetone phosphate

step 4 product

DHAP G3P

Step 4 enzyme

Aldolase

Step 5

Dihydroxyacetone phosphate » glyceraldehyde 3-phosphate

step 5 product

G3P

Step 5 enzyme

Triose Phosphate Isomerase

Step 6

Glyceraldehyde 3-phosphate + NAD+ + Pi » 1,3-biphosphoglycerate + NADH

step 6 product

1,3-bisphosphoglycerate

Step 6 enzyme

Glyceraldehyde-3-phosphate dehydrogenase

Step 7

1,3-bisphosphoglycerate + ADP » 3-phosphoglycerate + ATP

step 7 product

3-phosphoglycerate

Step 7 enzyme

Phosphoglycerate Kinase

Step 8

3-phosphoglycerate » 2-phosphoglycerate

step 8 product

2-phosphoglycerate

Step 8 enzyme

Phosphoglycerate Mutase

Step 9

2-phosphoglycerate » phosphoenolpyruvate

step 9 product

PEP

Step 9 enzyme

Enolase

Step 10

Phosphoenolpyruvate + ADP » pyruvate + ATP

step 10 product

pyruvate

Step 10 enzyme

Pyruvate Kinase

mechanism of step 2

isomerization from aldose to ketose (ene-diol intermediate); G6P is rearranged to F6P

mechanism for step 4

a C6 intermediate is cleaved to two C3s. A covalent Schiff base intermediate is formed between the substrate and an ative-site of lysine; F1,6BP is split into DHAP and G3P

mechanism for step 6

• oxidation and phosphorylation; covalent catalysis occurs and a nicotinamide enzyme is used; G3P + NAD+ + P is converted to 1,3BPG and NADH

• G3P is oxidized: NAD+ gains electrons

• G3P is phosphorylated at C1

mechanism for step 8

phosphoryl transfer from C3 to C2 via a phospho-histidine intermediate; 3PG » 2PG

mechanism for step 10

activation via F-1,3-BP and AMP, inhibition via ATP and acetyl-CoA; PEP + ADP » pyruvate + ATP

mechanism for step 5

ene-diol intermediate via Glu165 active site; DHAP ←→ G3P

what steps involve the release of a secondary product?

• step 1:

  • ATP is invested and ADP is given off

• step 3:

  • ATP is invested and ADP is given off

• step 6:

  • NAD+ is invested and NADH is given off

• step 7:

  • ADP is invested and ATP is produced

• step 9:

  • water is produced in the production of PEP

• step 10:

  • ADP is invested and ATP is produced

why is water produced in step 9?

because 2-phosphoglycerate loses two hydrogens and an oxygen to form a double bond in the formation of PEP; PEP has the same structure as 2-phosphoglycerate but it is missing an oxygen on C3 and has a newly formed double bond between C2 and C3

what step produced NADH from NAD+

step 6

in what steps is ADP invested and ATP produced

step 7 and 10

in what steps is ATP invested and ADP given off?

step 1 and 3

how is step 1 regulated

• via G6P

• own product inhibits its formation

• hexokinase gets inhibited

how is step 3 regulated

• inhibited: ATP/Citrate

• activated: AMP and F-2,6-BP

• PFK-1 activity regulation

how is step 10 regulated

• inhibited: ATP/AcCoA

• activated: F-1,6-BP/AMP

• pyruvate kinase activity regulated