Figure 3.

CCEU and ICEU alkylate common and specific B16 cell proteins. 2D electrophoresis on 3–10 nonlinear pH range strips: proteins were extracted from B16 cells treated for 24 h with 100 μM CCEU (a) or 100 μM ICEU (b), unlabelled (left) or radiolabelled ([¹⁴C]-CCEU, 19 GBq/mmol and [¹²⁵I]-ICEU, 1.5 GBq/mmol) (right). They were stained with colloidal blue (left) or dried before autoradiography of ¹⁴C or ¹²⁵I (right, a and b, respectively). Spots equivalent to the radioactive spots (numbers) were recovered on Coomassie-stained gels and identified by MALDI-TOF-MS. From the six major labelled spots, spots 1–5 were alkylated by both CEUs whereas spots 6-a and 6-b were specifically identified after CCEU or ICEU treatment, respectively. ^* Corresponds to radiolabelled materials that could not be identified, as they did not correspond to defined spots on a coloured gel. CCEU, cyclohexylphenyl-chloroethyl urea; ICEU, iodophenyl-chloroethyl urea; MALDI-TOF-MS, matrix-assisted laser desorption/ionisation–time of flight–mass spectrometry.