Fig. 3

a pH dependency of the Cc XylC lactonase measured using circular dichroism. A circular dichroism (CD)—based assay for lactonase activity was performed in 10 mM Tris–HCl buffer, pH 6–8, using 1 mM lactone and 3.4 µg of enzyme (in case it was added to the reaction) in 300 µL buffer. b NMR based Cc XylC lactonase activity measurements. The reactions for NMR were carried out in 600 µl of 50 mM Na-phosphate buffer, pH 6.8 at 22 °C containing 10% of D₂O using 2 mM xylonolactone with 100 µM metal ions or EDTA. After recording a zero spectrum 10 µg of Cc XylC was added