A systematic investigation of Escherichia coli central carbon metabolism in response to superoxide stress

BMC Systems Biology

Table 3 Changes in enzyme activities following PQ stress^a

Enzymes	Metabolic steps	Activity normal conditions	Activity paraquat treated	PQ/normal Ratios
IDH	icd	0.301 ± 0.009	0.155 ± 0.010	0.51
AKGDH	akd	0.191 ± 0.008	0.090 ± 0.015	0.47
MDH	mdh	0.106 ± 0.003	0.303 ± 0.013	2.86
G6PDH	gdh	0.428 ± 0.000	1.219 ± 0.011	2.85
PGI	hxi	0.207 ± 0.003	0.297 ± 0.007	1.44
ICL	gs1	0.787 ± 0.012	1.506 ± 0.004	1.91
ENO	eno	0.072 ± 0.012	0.072 ± 0.013	1.00
THD	-	0.122 ± 0.005	0.181 ± 0.003	1.48

^aEnzyme activities in cell extracts of control or paraquat-treated wildtype E. coli JM101 grown on glucose at D = 0.17 h^-1 under aerobic chemostat conditions. Ratio calculation was based on control conditions (wildtype aerobic growth on glucose). The unit of enzyme activity is μmol min^-1 (mg protein) ^-1. All measurements were performed in triplicate. Data are expressed as means ± S.D. IDH: isocitrate dehydrogenase NADP-dependent, AKGDH: α-ketoglutaric acid dehydrogenase, PGI: glucose phosphate isomerase, MDH: malate dehydrogenase, G6PDH: glucose-6-phosphate dehydrogenase, ICL: isocitrate lyase, ENO: enolase, THD: transhydrogenase.

ISSN: 1752-0509