  The systematic investigations of the role of the virtual charm axial currents
in the decay of $B$-mesons to $\eta '$ $K$ and the spin structure of the
nucleon are performed. We reduce the divergence of the virtual charm axial
current to a specific gluon operator. Since this operator receives the main
contribution from topologically nontrivial components of the QCD vacuum, we
rederive the Dyakonov-Petrov Effective Action, based on the instanton QCD
vacuum model. This action is applied to the calculations of the coupling of
$\eta '$ to the charm axial current and found $f_{\eta '}^{(c)} (\mu \simeq
m_c) = - (12.3 \sim 18.4 {\rm MeV}), $ providing a possibility for the
explanations of the recent experimental data on $B \to \eta ' K$-decay.
Analogous calculations of the virtual charm content of the nucleon spin leads
to $\Delta c (\mu \simeq m_c) = - (0.015 \sim 0.024),$ which is one order of
magnitude smaller than the analogous contribution of the strange quark.
