Humboldt State University ® Department of Chemistry

Richard A. Paselk

Chemistry 438 - Spring 2013

Kreb's TCA Cycle

Review aerobic pathway energy generation:

 Reaction
 Energy Product

factor
ATP Equivalents
(@2.5 ATP/NADH)
ATP Equivalents
(@3 ATP/NADH)
Hexokinase ADP 1 -1 -1
PFK  ADP 1 -1 -1
Ga-3-P DH NADH 2 5 6
PGA Kinase ATP 2 2 2
Pyruvate Kinase ATP 2 2 2
Pyruvate DH Complex

 NADH

 2

5
 6
Isocitrate DH NADH

2

5
 6
2-oxoglutarate DH Complex NADH

2

5
 6
Succinyl-CoA Synthetase GTP

2

2
 2
Succinate DH FADH2

2

3
 4
Malate DH NADH

2

5
 6

  TOTAL=

32
 38

 

 

 

 

 

 

 

 

 

 

 

 

 

 Reaction
 Energy Product

factor
ATP Equivalents
(@2.5 ATP/NADH)
Pyruvate DH Complex NADH

1

2.5
Isocitrate DH NADH

1

2.5
2-oxoglutarate DH Complex NADH

1

2.5
Succinyl-CoA Synthetase GTP

1

1
Succinate DH FADH2

1

1.5
Malate DH NADH

1

2.5

  TOTAL=

12.5

 

 

 

 

 

 

 

 

 

 

 

 

 

* Note that the energy yield in this step is shuttle and thus tissue dependent. For tissues using the glycerol-P shuttle get 1.5, whereas for tissues using the malate-aspartate shuttle get 2.5.

 Reaction
 Energy Product

factor
ATP Equivalents
(@2.5 ATP/NADH)
Lactate DHcytosol (Lac  Pyr) NADH

1

(1.5) 2.5*
Pyruvate DH Complex

 NADH

 1

 2.5
Isocitrate DH NADH

1

2.5
2-oxoglutarate DH Complex NADH

1

2.5
Succinyl-CoA Synthetase GTP

1

1
Succinate DH FADH2

1

1.5
Malate DH NADH

1

2.5

  TOTAL=

(13.5) 15

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 Reaction
 Energy Product

factor
ATP Equivalents
(@2.5 ATP/NADH)
2-oxoglutarate DH Complex NADH 1 2.5
Succinyl-CoA Synthetase GTP 1 1
Succinate DH FADH2 1 1.5
Malate DHcytosol NADH 1 2.5
PEP Carboxykinase GDP 1 -1
Pyruvate kinase ATP 1 1
Pyruvate DH Complex NADH 1 2.5
Isocitrate DH NADH 1 2.5
2-oxoglutatrate DH Complex NADH 1 2.5
Succinyl-CoA Synthetase GTP 1 1
Succinate DH  FADH2 1 1.5
Malate DH NADH 1 2.5

  TOTAL =

20

 

 

 

 

 

 

 

 

 

 

 

 

 Reaction
 Energy Product

factor
ATP Equivalents
(@2.5 ATP/NADH)
Malate DHmitosol(oxal mal) NAD+ 1 -2.5
Malate DHcytosol NADH 1 2.5
PEP Carboxykinase GDP 1 -1
Pyruvate kinase ATP 1 1
Pyruvate DH Complex NADH 1 2.5
Isocitrate DH NADH 1 2.5
2-oxoglutatrate DH Complex NADH 1 2.5
Succinyl-CoA Synthetase GTP 1 1
Succinate DH  FADH2 1 1.5
Malate DH NADH 1 2.5

  TOTAL=

12.5*

*Note the number of ATPs is identical to that generated from pyruvate—compare them in terms of oxidation of the carbons, does this make sense?
 

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©R A Paselk

Last modified 9 April 2013