Evidence of allosteric alteration of CRPMt and CRPBCG by cAMP. CRPMt and CRPBCG were digested with 0.2 μg (A), 0.02 μg (B), or 0.1 μg (C) trypsin. Lanes: M, broad-range molecular markers (Promega); 1 to 4, CRPMt; 5 to 8, CRPBCG. Lanes 4 and 8 are undigested controls. Lanes 1 to 3 and 5 to 7 were digested with trypsin; 100 μM cAMP was supplemented in lanes 2 and 6; 100 μM AMP was supplemented in lanes 3 and 7. Figures are representative of at least two independent experiments.