Copper binding to rMBPPfCox11Ct is inhibited by EDTA and measured by atomic absorption spectroscopy. Affinity purified rMBPPfCox11Ct or rMPB were incubated with and without EDTA and with CuCl2 in vitro. Copper was detected with the BCA release assay without (open bars) or with (closed bars) the addition of ascorbic acid. Results are the means ± SE of triplicate measurements from duplicate samples. A two-way ANOVA with Bonferroni multiple comparison tests were conducted on results of samples incubated with CuCl2 in the presence of ascorbate. Comparisons are between rMBPPfCox11Ct or rMPB without and with EDTA, *P < 0.001. A, B Affinity purified rMBPPfCox11Ct or rMPB was incubated with CuCl2 in the absence (open bars) or presence (solid bars) of ascorbic acid and bound copper was quantified using atomic absorption spectroscopy at 324.5 nm. Data is the mean ± SD of duplicate samples.