PMC

V_max of LDH at different dilutions of cell extract. The activity at each dilution is an average of duplicate measurements, and error bars represent deviations from the average.

Ratio of V_max to measured fluxes for chemostat cultures at D = 0.15 h⁻¹ (white bars) and for batch cultures with measured fluxes from the work of Even et al. () (gray bars) and from the work of Nordkvist et al. () (black bars). Error bars represent standard deviations of a ratio of average fluxes from three independent cultures.

V_max values obtained in the in vivo-like assay medium (white bars) and those reported in the literature () (squares) for batch culture of L. lactis MG 1363. Error bars on the white bars represent standard deviations of average activities from two independent batch cultures.

(a) Relative V_max of PYK in the presence of 5 mM FBP and varying concentrations of inorganic phosphate, normalized to PYK V_max in the absence of phosphate. (b) Relative V_max at pH 7.5 in HEPES buffer, normalized to V_max in Tris-HCl buffer. (c) Relative activities of LDH (white bars), PYK (gray bars), and GAPDH (black bars) with varying potassium glutamate concentrations normalized to activities in the absence of potassium glutamate. (d) V_max values with 1/10 the metals present in CDMPC, relative to V_max values without metals added to the assay buffer. Error bars represent standard deviations of a ratio (see the supplemental material) of average activities from at least three independent dilutions of a single cell extract. ACK, acetate kinase; G6PDH, glucose-6-phosphate dehydrogenase.

(a) V_max values of enzymes containing coupling enzymes in assays without ammonium sulfate relative to those with ammonium sulfate in the assay. (b) V_max values measured in batch-grown cell samples frozen for 3 days relative to those obtained in fresh cells. (c) Relative V_max values showing loss of enzyme activity during storage of cell samples at −20°C at 4 days (white bars), 12 days (gray bars), and 4 months (black bars) from the day of harvesting the chemostat at D of 0.15 h⁻¹. Error bars represent standard deviations of a ratio of average activities from at least three independent dilutions from two independent batch cultures for panels a and b and from the cell extract of the chemostat culture for panel c.