9. Glycolysis And Tca Cycle - Shuttles

GLYCOLYSIS & TCA CYCLESHUTTLES GLUCOSE

ATP ADP

Glucose-6-P Fructose-6- P

ATP ADP

Fructose-1,6-bis- P Glycerone-3- P (Di-OH-acetone- P) 2 3-P-Glyceraldehyde

2NAD 2 Pi

2 1,3-bis-P-Glycerate

2 NADH+H+

2 ADP 2 ATP

2 3-P-Glycerate 2 2-P-Glycerate 2H2O 2 ADP

2 P-enolpyruvate

2 ATP

2 PYRUVATE

NADH+H+

NAD+

PYRUVATE

-OOCCH(OH)CH COO2

-OOCCH(OH)CH COO2

ACETYL-CoA

Malate

Citrate

-OOCCOCH COO2

Oxaloacetate 2-Oxoglutarate

Malate

Oxaloacetate 2-Oxoglutarate

Aspartate

NADH+H++

Isocitrate

Aspartate

1H+

1H+

Glutamate

Glutamate

2-Oxoglutarate FADH2 UQ

2H+

HOCH2CH(OH)CH2OP

Glycerol-3-P

FAD

FAD

H H OOCCH-CHCOOUQH2

HOCH2COCH2OP

Succinate

2e-

Pi GTP

~1.5ATP

NAD+

FADH2

Succinyl-CoA GDP

UQH2

Di-OH-acetone-P

UQ 2H+

~1.5 ATP 2e-

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-phosphate 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 and forms ATP. This is a pathway similar to that in which succinate is aerobically oxidised and they each result in the formation of approximately 1.5 mols of ATP

GLYCEROL PHOSPHATE SHUTTLE

Fumarate

MALATE-ASPARTATE SHUTTLE

Oxaloacetate

Malate