BCH100 ATP and Steps

2.5 ATP per NADH

NADH produces 2.5 ATP in oxidative phosphorylation

1.5 ATP per FADH2

FADH2 produces 1.5 ATP in oxidative phosphorylation

1 ATP per GTP

GTP is energetically equivalent to 1 ATP

2 ATP invested

Amount of ATP used in glycolysis investment phase per glucose

4 ATP produced

Total ATP made in glycolysis payoff phase per glucose

2 ATP net (glycolysis)

Net gain of ATP from glycolysis per glucose molecule

2 NADH (glycolysis)

NADH molecules generated in glycolysis per glucose

Shuttle yields

1.5 ATP per NADH via glycerol-3-phosphate shuttle, 2.5 via malate-aspartate

2 NADH (PDC)

NADH produced by pyruvate dehydrogenase complex per glucose

3 NADH, 1 FADH2, 1 GTP (TCA per AcCoA)

TCA cycle products from 1 acetyl-CoA

6 NADH, 2 FADH2, 2 GTP (TCA per glucose)

TCA cycle products from 1 glucose (2 turns)

Activation cost 2 ATP

Energy cost to activate fatty acid for β-oxidation

Per β-oxidation round

1 FADH2, 1 NADH, 1 acetyl-CoA (except final round yields 2 acetyl-CoA)

Palmitoyl-CoA totals

31 NADH, 15 FADH2, 8 GTP produced from full C16 oxidation

106 ATP net (C16)

Total ATP yield from C16 fatty acid (palmitoyl-CoA) including GTP, after subtracting 2 ATP activation cost

4 ATP, 2 GTP, 2 NADH cost

Energy cost to synthesize one glucose from two pyruvate in gluconeogenesis

3 ATP (glycogen)

ATP gained when glucose is released from glycogen as G6P into glycolysis

PFK-1

Committed and rate-limiting step enzyme of glycolysis

Pyruvate carboxylase & PEPCK

Enzymes that bypass pyruvate kinase step in gluconeogenesis

FBPase-1

Enzyme that bypasses phosphofructokinase-1 in gluconeogenesis

Glucose-6-phosphatase

Enzyme that bypasses glucokinase/hexokinase in gluconeogenesis (final step)

PDH E1

Regulated subunit of the pyruvate dehydrogenase complex

Citrate synthase

Rate-limiting enzyme of TCA cycle that initiates citrate formation

Isocitrate dehydrogenase & α-KG dehydrogenase

Irreversible, regulated steps in the TCA cycle

Carnitine acyltransferase-I

Rate-limiting step for fatty acid entry into mitochondria

Acetyl-CoA carboxylase (ACC)

Rate-limiting enzyme of fatty acid synthesis (forms malonyl-CoA)

CPS I

Committed enzyme of urea cycle that uses NH4⁺ to make carbamoyl phosphate

Aspartate transcarbamoylase

Committed step enzyme of pyrimidine synthesis

PRPP-glutamine amidotransferase

Committed step enzyme of purine synthesis