Catalase inhibits DBBF-Hb oxidation, G2/M arrest, and apoptosis.

(A) Reaction mixtures containing 50 μM DBBF-Hb, with or without 100 U/mL catalase, were incubated with or without GOX (2 or 10 mU/mL). Percentages of HbFe²⁺ were measured at 2-minute intervals for 2 hours using the Winterbourn equations. Representative tracings of 1 of 4 experiments are shown. (B) Proportion of G2/M cells measured after a 9-hour incubation with medium alone or 50 μM DBBF-Hb and GOX (2 or 10 mU/mL) in the presence or absence of 100 U/mL catalase. Each value represents the mean ± SE of 3 to 6 independent experiments. (C) PS externalization measured after 18 hours for the same treatments as in panel B. Each value represents the mean ± SE of 3 to 6 independent experiments. *P < .05 versus medium alone; +P < .05 versus 2 mU/mL GOX.