PCAC relation for Dstar -> D axial form factors

A relation among the form factors of $ $ at $q^2 \to 0$ is derived. It is verified to lowest order in both the $1/M_c$ expansion and the expansion in number of derivatives using the effective lagrangian that incorporates the heavy quark symmetries for the b and c quarks, and the chiral symmetry for the u, d, s quarks. % (Contributed note to the Proceedings of the "Workshop on B Physics at Hadron Accelerators", Snowmass, Colorado (USA)).