Figure 5. Quantification of active cysteine cathepsins using a specific active site directed probe.

Polyps from APC^Δ468, Ctsb^−/− APC^Δ468, and anti-TNFα treated APC^Δ468 mice were micro-dissected, pooled, and extracts were incubated with DCG-04 prior to electrophoresis on a 4–12% gradient SDS gel and western blotting; healthy adjacent regions were similarly analyzed. Active Cathepsins were visualized with the use of chemiluminescence reagents. (a) A representative blot. (b) Average Optical Densities (OD) from each band of three independent blots, measured with Image J software; values were normalized with the OD of the β-actin protein, detected using a specific antibody. Open bars: Cathepsin Z, black bars: Cathepsin B.