. 2012 Aug 29;6:114. doi: 10.1186/1752-0509-6-114

Table 2.

Metabolic and physiological functions tested for the metabolic network

Classification		Metabolic function	Cellular function	Reference
1. Carbohydrates
	∙ Monosaccharides	Glucose and fructose metabolism	Energy production	[28,29]
		Glycogen formation	short-term energy storage	[22]
		Ribose	Energy production	[30,31]
			Formation of ribonucleotides
2. Carboxylic acids		Degradation of ketone bodies	Energy production during fasting	[32,33]
			and diabetes
3. Lipids
	∙ Cholesterol	De novo synthesis (cytosol, peroxisome)	Membrane synthesis	[34,35]
	∙ Fatty acids	Formation of (semi)-essential fatty acids	Membrane synthesis	[36,37]
		β-oxidation of (non)-essential fatty acids	Energy production	[38-40]
	∙ Triacylglycerides	De novo synthesis/ degradation of Mono-,	Membrane synthesis	[41,42]
		Di- and Triacylglycerides
	∙ Phospholipids	De novo synthesis/ degradation of:	Membrane formation	[15,16,41,43-45]
		∘ Phosphatidylserines
		∘ Phosphatidylcholines
		∘ Lysophosphatidylcholines
		∘ Phosphatidylethanolamines
		∘ Phosphatidylinositol
		∘ Sphingomyelin
		∘ Cardiolipin
	∙ Sphingolipids	Ceramides	Membrane formation, apoptosis	[46]
4. Proteins
	∙ Amino acids	Formation of (non)-essential amino acids	Precursors of cellular proteins, nucleic acids,	[47,48]
			glutathione and thioredoxin
		Degradation of (non)-essential amino acids	Amino acid homoeostasis,	[49]
			anaplerotic reactions of TCA cycle
		Glutamine formation	Ammonia detoxification, Protein	[50]
			de novo synthesis
		De novo synthesis of L-Carnitine	Transport of fatty acids from cytosol into	[51,52]
			mitochondria during β-oxidation
	∙ Tripeptide	De novo synthesis of Glutathione	Prevention of cellular damage due to ROS	[53]
	∙ Polyamines	Formation/ degradation of Prutescine and Spermidine	Cell growth and division	[54,55]
	∙ Proteins	De novo synthesis of:
		Myosin, Titin, α-Sarcoglycan, Tropomyosin, Troponin T	Contractile apparatus, enabling muscular contraction	[56,57]
		De novo synthesis of Thioredoxin	Prevention of cellular damage due to ROS	[47,48]
5. Nucleic acids
	∙ Nucleobases	De novo synthesis/ degradation of purine	Precursors of nucleosides, deoxy-ribonulceotides	[58,59]
		and pyrimidine nucleotides	and ribonucleotides
		Salvage of purine and pyrimidine nucleotides	Maintaining energy state	[60]
		De novo synthesis/ rephosphorylation of:
		∘ nucleosides (ATP, CTP, GTP, TTP, UTP)	Energy production for muscular contraction	[59,61-63]
		∘ NADH, NADPH	Energy production and providing redox-state	[64,65]