Effect of cell growth rate on fumarase activity in continuous culture. (A) Cells were grown in glucose (2.25 mM) minimal medium at the indicated growth rates. The oxygen level was 1%. (B) Cells were grown in acetate (2.25 mM) minimal medium, and the oxygen level was 1%. (C) Cells were grown in glucose (2.25 mM) minimal medium, and the oxygen level was 21%. Total fumarase activity in W3110 (●), FumA+B activity in W3110 (○), FumC activity in W3110 (▴), and total fumarase activity in EJ1535 (FumA− FumC−) (▵) were determined.