Sodium borate ph 8

To assess LOX enzymatic activity in CM, a fluorometric assay detecting the level of hydrogen peroxide was performed as previously described [32 (link)] using a freshly prepared enzyme mixture containing 1.2 M urea (Sigma-Aldrich), 50 mM sodium borate pH 8.0 (Sigma-Aldrich), 0.01 M calcium chloride (Sigma-Aldrich), and 1.0 U/mL horseradish peroxidase (Sigma-Aldrich), followed by 50 μL of freshly prepared substrate mixture containing 1.2 M urea (Sigma-Aldrich), 50 mM sodium borate pH 8.0 (Sigma-Aldrich), 0.01 M calcium chloride (Sigma-Aldrich), 0.01 M diaminopentane (Sigma-Fluka), and 10 μM amplex red (Invitrogen). To determine lactate dehydrogenase (LDH)-release conditioned media was harvested from sham-treated and irradiated A549 cells, 24 hours after irradiation, LDH-activity was determined using the CytoTox 96 Non-Radioactive Cytotoxicity Assay (Promega). Purified LDH was used as a positive control.