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TABLE 17.2 Citric acid cycle

Step	Reaction	Enzyme	Prosthetic group	Type*	A G°	t
					kcal mol^-1	kj mol”^1
1	Acetyl Co A 4- oxaloacetate 4- H ?0-»	Citrate synthase		a	-7.5	-31.4
	citrate 4- CoA 4- H ^+
2a	Citrate-cis-aconitate 4- H?0	Aconitase	Fe-S	b	+2.0	+8.4
2b	cis-Aconitate 4- H 20-± isocitrate	Aconitase	Fe S	c	-0.5	-2.1
3	Isocitrate 4- NAD"*"	Isocitrate		d 4- e	-2.0	-8.4
	a-ketoglutarate 4- C02 4- NADH	dehydrogenase
4	a-Ketoolutarate 4- NAD ^ł 4 (.oA	a-Ketoglutarate	Lipoic acid,	d 4- e	-7.2	-30.1
	succinyl CoA 4- CO> 4* NADH	dehydrogenase	FAD, TPP
		complex
5	Succinyl CoA 4- P; 4- GDP--	Succinyl CoA		f	-0.8	-3.3
	succinate 4- GTP 4- CoA	synthetase
6	Succinate 4- FAD (enzyme-bound)-**	Succinate	FAD. Fe S	e	-0	0
	fumarate 4- FADH2 (enzyme-bound)	dehydrogenase
7	Fumarate 4- H20 L-malate	Fumarase		c	-0.9	-3.8
8	l.-Malate + NAD+-*	Malate		e	+7.1	+29.7
	oxaloacetate 4- NADH 4- H ^ł	dehydrogenase

♦Reaction type: (a) condensation; (b) dehydration; (c) hydration; (d) decarboxylation; (e) oxidation; (0 substralc-levcl phosphorylation.

NADH i FADH ^są dalej utleniane w łańcuchu oddechowym przekazując elektrony na O), co dostarcza energii do syntezy ATP:

Z = 10 cz. ATP (glikoliza = 2 cz. ATP)

3 x NADH = 3 x 2.5 ATP 1xFADH2=1.5 ATP 1 cz. GTP