Citric Acid Cycle (C.A.C.)

Mitochondrial Structure (cont.)

TCA Cycle

C

C

O-

Step 1

CO

O-

CO

O

Oxaloacetate

OH

C

||O

S CoA

C

O-

CO

C

O-

CO

C

O-

CO

Co - ASH

Citrate Synthase

Citrate (3° Alcohol)

CH3

Step 2 & 3

HO

C

O-

CO

C

O-

CO

C

O-

CO

H

H2OC

O-

CO

C

O-

CO

C

O-

CO

C

O-

CO

C

O-

CO

C

O-

CO

H

HO

Citrate

Aconitase

Aconitate Isocitrate (2° alcohol)

Step 4

C

O-

CO

C

O-

CO

C

O-

CO

HO

H

C

O-

CO

C

O-

CO

C

O-

CO

O

NAD+ NADH + H+

Isocitrate

Dehydrogenase

Isocitrate Oxalosuccinate

CONT. NEXT SLIDE

C

O-

CO

C

C

O-

CO

O

CO2

- keto glutarate

Classic biological redox Rx.

2° alcohol oxidized to a keto

NAD+ reduced.

• Carboxylic acids that are to a keto group spontaneously decarboxylate.

Step 5

Step 6

C

O-

CO

C

C

O-

CO

O

- keto glutarate

NAD+ NADH + H+

CoASHCO2 C

O-

CO

C

C SO

CoA

Succinate Co-A

PGTP = 8 Kcal/m

- keto dehydrogenase

CONT. NEXT SLIDE

CoASH

H2O

GDP

GTP

ATP

ADP

C

O-

CO

C

C

O-O

Succinate

Succinate Synthetase

Step 7

C

O -C

O

Succinate

HH

FAD FADH2

S.D.H

Malate

HOH

Fumarate

C HH

CO

O -

C

O -C

O

H

CH

CO

O -

CO -

CO

HHO

C HH

CO

O -

NAD + NAOD + H +

CO -

CO

O

C

CO

O -

O.A.A

Fumarase M.D.H

Trans Dehydrogenation 2° Alcohol

Oxidized to keto

NADH +

Step 8, 9, 10