Table 4.

ES and EFM for the minimal network depicted in figure 1. (The enzymes participating in the ES and EFM are weighted with their fractional flux. Negative values indicate the reaction is used in the reverse sense. For abbreviations, see table 2. Schemes for all the ES can be retrieved from: http://bioinfo.cipf.es/tgabaldon/minimal_metabolism.html.)

ES	overall reaction	participating enzymes and fluxes
1	nadh+ser+dctp→nad+Jo10+Jo11	DFR GHT NDK7 NDK8 TMK1 TMK2 Jo11 Jo10 DCD THY
2	gdp+pyr+adp+p→pep+atp+Jo1	ENO GAP GPM LDH PGK Jo1
3	f6p+atp→gdp+dhp+adp	FBA PFK
4	gdp↔dhp	TPI
5	pep+Ji1→f6p+pyr	PGI PTS Ji1
6	nadh+Jk2↔nad+Jk1	−Jk1 Jk2
7	f6p+3 gdp+3 atp→p+3 amp+3 prpp	TKT1 –TKT2 FBA2 (2 RPE) (2 RPI) SPH (3 PRS)
8	atp+gdp→adp+Jo5	NDK1 Jo5
9	2 atp+prpp+Ji5→pp+2 adp+utp	NDK2 Ji5 UPP CMK
10	atp+nadh→nad+Jo7	NDK3 Jo7 NRD1
11	atp+nadh+gdp→adp+nad+Jo9	NDK4 Jo9 NRD2
12	adp+ctp↔atp+cdp	NDK5
13	atp+nadh+cdp→adp+nad+dctp	NDK6 NRD3
14	Ji7↔p	Ji7
15	pp→2 p	PPA
16	pep+adp→pyr+atp	PYK
17	dhp+atp+nadh+ctp+ser+2 Ji2→pp+adp+nad+cdp+Jo2	Jo2 (2 Ji2) PLSb PLSc CDS PSS PSD GPS CMK2
18	atp→Jo3	Jo3
19	prpp+Ji3→pp+amp	Ji3 HPT1
20	atp+prpp+Ji4→pp+adp+Gdp	Ji4 HPT2 GMK
21	Ji6→ser	Ji6
22	atp+amp→2 adp	ADK
23	ctp→Jo4	Jo4
24	utp→Jo6	Jo6
25	dctp→Jo8	Jo8
26	utp→ctp	PYR

EFM	overall reaction	participating enzymes	function
1	2 glc+2 pal+ser+p+nadh=3 lac+peta+nad	(3 ENO) (2 FBA) –TPI (3 GAP) (3 GPM) (3 LDH) (2 PGI) (3 PGK) –NDK5 PPA (2 PTS) (2 PFK) PYK PLSb PLSc CDS PSS PSD GPS CMK2	membrane phospholipid synthesis
2	21 glc+6 ade+18p=32 lac+6 atp	(16 ENO) (9.5 FBA) (−9.5 TPI) (16 GAP) (16 GPM) (16 LDH) (10.5 PGI) (16 PGK) TKT1 –TKT2 FBA2 (2 RPE) (2 RPI) (3 PPA) (10.5 PTS) (9.5 PFK) (5.5 PYK) SPH (3 PRS) (6 ADK) (3 HPT1)	ATP synthesis
3	21 glc+6 ade+18 p+6nadh=32 lac+6 datp+6 nad	(16 ENO) (9.5 FBA) (−9.5 TPI) (16 GAP) (16 GPM) (16 LDH) (10.5 PGI) (16 PGK) TKT1 –TKT2 FBA2 (2 RPE) (2 RPI) (3 NDK3) (3 PPA) (10.5 PTS) (9.5 PFK) (5.5 PYK) SPH (3 PRS) (6 ADK) (3 HPT1) (3 NRD1)	dATP synthesis
4	21 glc+6 gua+18p=32 lac+6 gtp	(16 ENO) (9.5 FBA) (−9.5 TPI) (16 GAP) (16 GPM) (16 LDH) (10.5 PGI) (16 PGK) TKT1 –TKT2 FBA2 (2 RPE) (2 RPI) (3 NDK1) (3 PPA) (10.5 PTS) (9.5 PFK) (5.5 PYK) SPH (3 PRS) (3 ADK) (3 HPT2) (3 GMK)	GTP synthesis
5	21 glc+6 gua+18 p+6 nadh=32 lac+6 dgtp+6 nad	(16 ENO) (9.5 FBA) (−9.5 TPI) (16 GAP) (16 GPM) (16 LDH) (10.5 PGI) (16 PGK) TKT1 –TKT2 FBA2 (2 RPE) (2 RPI) (3 NDK4) (3 PPA) (10.5 PTS) (9.5 PFK) (5.5 PYK) SPH (3 PRS) (3 ADK) (3 HPT2) (3 GMK) (3 NRD2)	dGTP synthesis
6	21 glc+6 ura+18 p=32 lac+6 utp	(16 ENO) (9.5 FBA) (−9.5 TPI) (16 GAP) (16 GPM) (16 LDH) (10.5 PGI) (16 PGK) TKT1 –TKT2 FBA2 (2 RPE) (2 RPI) (3 NDK2) (3 PPA) (10.5 PTS) (9.5 PFK) (5.5 PYK) SPH (3 PRS) (3 ADK) (3 UPP) (3 CMK)	UTP synthesis
7	21 glc+6 ura+18 p=32 lac+6 ctp	(16 ENO) (9.5 FBA) (−9.5 TPI) (16 GAP) (16 GPM) (16 LDH) (10.5 PGI) (16 PGK) TKT1 –TKT2 FBA2 (2 RPE) (2 RPI) (3 NDK2) (3 PPA) (10.5 PTS) (9.5 PFK) (5.5 PYK) SPH (3 PRS) (3 ADK) (3 UPP) (3 CMK) (3 PYR)	CTP synthesis
8	21 glc+6 ura+18 p+6 nadh=32 lac +6 dctp +6 nad	(16 ENO) (9.5 FBA) (−9.5 TPI) (16 GAP) (16 GPM) (16 LDH) (10.5 PGI) (16 PGK) TKT1 –TKT2 FBA2 (2 RPE) (2 RPI) (3 NDK2) (3 NDK5) (3 NDK6) (3 PPA) (10.5 PTS) (9.5 PFK) (5.5 PYK) SPH (3 PRS) (3 ADK) (3 UPP) (3 CMK) (3 NRD3) (3 PYR)	dCTP synthesis
9	21 glc+6 ura+6 ser +18 p+12 nadh=32 lac+6 ttp+12 nad+6 gly	(3 DFR) (3 GHT) (16 ENO) (9.5 FBA) (−9.5 TPI) (16 GAP) (16 GPM) (16 LDH) (10.5 PGI) (16 PGK) TKT1 –TKT2 FBA2 (2 RPE) (2 RPI) (3 NDK2) (3 NDK5) (3 NDK6) (3 NDK7) (3 NDK8) (3 TMK1) (3 TMK2) (3 PPA) (10.5 PTS) (9.5 PFK) (5.5 PYK) SPH (3 PRS) (3 ADK) (3 UPP) (3 CMK) (3 NRD3) (3 PYR) (3 DCD) (3 THY)	TTP synthesis
10	33 glc+12 pal+6 ura+6 ser+24 p+12 nadh=50 lac+6 peta+6 dctp+12 nad	(25 ENO) (15.5 FBA) (−12.5 TPI) (25 GAP) (25 GPM) (25 LDH) (16.5 PGI) (25 PGK) TKT1 –TKT2 FBA2 (2 RPE) (2 RPI) (3 NDK2) (3 NDK6) (6 PPA) (16.5 PTS) (15.5 PFK) (8.5 PYK) (3 PLSb) (3 PLSc) (3 CDS) (3 PSS) (3 PSD) (3 GPS) SPH (3 PRS) (3 ADK) (3 UPP) (3 CMK) (3 CMK2) (3 NRD3) (3 PYR)	membrane phospholipid and dCTP synthesis
11	33 glc+12 pal+6 ura+12 ser+24 p+18 nadh=50 lac+6 peta+6 ttp+18 nad+6 gly	(3 DFR) (3 GHT) (25 ENO) (15.5 FBA) (−12.5 TPI) (25 GAP) (25 GPM) (25 LDH) (16.5 PGI) (25 PGK) TKT1 –TKT2 FBA2 (2 RPE) (2 RPI) (3 NDK2) (3 NDK6) (3 NDK7) (3 NDK8) (3 TMK1) (3 TMK2) (6 PPA) (16.5 PTS) (15.5 PFK) (8.5 PYK) (3 PLSb) (3 PLSc) (3 CDS) (3 PSS) (3 PSD) (3 GPS) SPH (3 PRS) (3 ADK) (3 UPP) (3 CMK) (3 CMK2) (3 NRD3) (3 PYR) (3 DCD) (3 THY)	membrane phospholipid and TTP synthesis