  In the anomaly equation for the singlet axial current the chiral limit of the
quark mass term does not vanish but comprises contribution from fermion zero
modes whose integral exactly cancels the topological charge arising from the
Adler-Bell-Jackiw anomaly. This signals chiral symmetry and opens a window for
restoring the status of Goldstone boson for the singlet $\eta^\prime$ without
having to invoke the large $N_c$ limit in the underlying QCD. We construct the
anomaly term in the effective action that incorporates the chiral symmetry
property and yet accounts for the excess mass of $\eta^\prime$ only when chiral
symmetry is broken explicitly by the quark masses. The anomaly term in the
present scenario thus plays the role of a catalytic agent that enhances the
mass of $\eta^\prime$ so that the singlet axial current obeys the popular PCAC
condition.
