  We present a lattice calculation of the renormalized running coupling
constant in symmetric (MOM) and asymmetric ($\widetilde{\rm MOM}$) momentum
substraction schemes including $u$, $d$, $s$ and $c$ quarks in the sea. An
Operator Product Expansion dominated by the dimension-two $\langle A^2\rangle$
condensate is used to fit the running of the coupling. We argue that the
agreement in the predicted $\langle A^2\rangle$ condensate for both schemes is
a strong support for the validity of the OPE approach and the effect of this
non-gauge invariant condensate over the running of the strong coupling.
