Optimal pH for activity of cathepsins. The activities of all cysteine cathepsins (Omni-cathepsin) and cathepsins S, B, K and D present in crude PBMC lysate were assayed using peptidase-specific fluorogenic substrates. The reaction buffer was adjusted so that the pH ranged from 2.0 to 9.0, fluorescence measured over time was plotted and the average maximum slope of the curve from three replicates was determined for each pH.
Vaithilingam et al. BMC Cell Biology 2013 14:35 doi:10.1186/1471-2121-14-35