1H

+

1H

+

2-Oxoglutarate

2-Oxoglutarate

Aspartate

Aspartate

Glutamate

Glutamate

Malate

Malate

Oxaloacetate

Oxaloacetate

Glycerone-3-P

Glycerol-3-P

NADH+H+

Citrate

Isocitrate

2-Oxoglutarate

Succinyl-CoA

ACETYL-CoA

PYRUVATE

i

P

+

GTP

-OOCCOCH2COO-

NAD+

NAD+

Glucose-6-P

Fructose-6-P

Fructose-1,6-bis- P

3-P-Glyceraldehyde

Glycerone-3-P

1,3-bis-P-Glycerate

3-P-Glycerate

2-P-Glycerate

ATP

ATP

ADP

ADP

NAD

2 Pi

NADH+H

+

ADP

ATP

H2O

ADP

ATP

(Di-OH-acetone- P)

P-enolpyruvate

PYRUVATE

2e-

Oxaloacetate

Malate

NADH+H

+

H H

GLUCOSE

2

2

2

2

2

2

2

2

2

2

2

2

2

GLYCOLYSIS & TCA CYCLE-

SHUTTLES

c

2000 IUBMB

FAD FAD

H

2

UQ

UQ

H

2

2H+

HOCH

2

C

H

(O

H

)CH

2

O

P

HOCH

2

COCH

2

O

P

(Di-OH-acetone-

P)

MALA

TE-ASP

ART

A

T

E

SHUTTLE

GL

YCEROL

PHOSPHA

TE

SHUTTLE

OOCC

H

-C

H

COO-

Fumarate

Succinate

Malate-Aspartate Shuttle

Operates when the NADH/NAD ratio is greater in the cytosol than in

the mitochondrial matrix. Electrons are transferred from cytosolic NADH via

malate

acoss the

the mitochondrial inner membrane

and re-forms NADH in the matrix. This shuttle requires the

translocation of 1proton for each malate

Glycerol-phosphte Shuttle

Operates if low ratio NADH/NAD in the cytosol - but at a cost.

Electrons are transferred (

via FAD) to ubiquinone

at the outer surface of the mitochondrial inner

membrane

to give ubiquinol

which remains in the membrane and feeds into the Electron

Transport Chain. This is a pathway similar to that in which succinate enters the chain, and in

each case there is a loss of 4 translocated protons - equivalent to 1ATP.

1.5 ATP

GDP

-OOCC

H

(O

H

)CH2COO-