  We check the impact of the factorization scheme employed in the calculation
of the heavy-quark deep-inelastic scattering (DIS) electro-production on the
PDFs determined in the NNLO QCD analysis of the world inclusive neutral-current
DIS data combined with the ones on the neutrino-nucleon DIS di-muon production
and the fixed-target Drell-Yan process. The charm-quark DIS contribution is
calculated in the general-mass variable-flavor-number (GMVFN) scheme: At
asymptotically large values of the momentum transfer $Q$ it is given by the
zero-mass 4-flavor scheme and at the value of $Q$ equal to the charm-quark mass
it is smoothly matched with the 3-flavor scheme using the
Buza-Matiounine-Smith-van Neerven prescription. The PDFs obtained in this
variant of the fit are very similar to the ones obtained in the fit with a
3-flavor scheme employed. Our 5-flavor PDFs derived from the 3-flavor ones
using the NNLO matching conditions are used to calculate the rates of
$W^{\pm}/Z$ and $t\bar{t}$ production at the Tevatron collider and the LHC at
NNLO.
