Lysates were routinely prepared by solubilisation of cells in RIPA buffer (0.1 M Tris-HCl, pH 7.4, 0.15 M NaCl, 1% (v/v) Triton X-100, 0.1% (v/v) Nonidet P-40). Protein concentrations were determined by bicinchoninic acid (BCA) protein assay [60] . Bovine serum albumin was used as a standard with a 50:1 ratio of 4% (w/v) CuSO 4 .5H 2 O.