at 25 C. 0.1 mL of the enzyme was added to the mixture containing 0.9 mL of 0.05 M sodium phosphate buffer at pH 7.0, 1.0 mL of 0.2 M catechol substrate solution in 0.05 M sodium phosphate buffer at pH 7.0, and 1.0 mL of RBE or CDRBE as an inhibitor.