  We investigate the equilibrium charge distribution along a single annealed
polyelectrolyte chain under different conditions. The coupling between the
conformation of the chain and the local charge distribution is described for
various solvent qualities and salt concentration. In salt free solution, we
find a slight charge depletion in the central part of the chain: the charges
accumulate at the ends. The effect is less important if salt is added to the
solution since the charge inhomogeneity is localized close to the chain ends
over a distance of order of the Debye length. In the case of poor solvent
conditions we find a different charging of beads and strings in the framework
of the necklace model. This inhomogeneity leads to a charge instability and a
first order transition between spherical globules and elongated chains.
