Singlet $VA\widetilde V$ correlator within the instanton vacuum model

The correlator of singlet axial-vector and vector currents in the external electromagnetic field is studied within the instanton liquid model of QCD vacuum. In the chiral limit we calculate the longitudinal $w_L^{(0)}$ and transversal $w_T^{(0)}$ with respect to axial-vector index invariant amplitudes at arbitrary space-like momentum transfer $q$. It is demonstrated how the anomalous longitudinal part of the correlator is renormalized at low momenta due to the presence of the $U_A(1)$ anomaly.