  We perform pQCD analysis of the existing DIS data for charged leptons with
account of corrections up to the NNLO. The parton distributions, value of
strong coupling constant, and high-twist terms are extracted and their
stability with respect to account of the NNLO corrections is analyzed. All the
quantities are generally stable within their experimental errors. Obtained
value of the strong coupling constant is $\alpha_s^{\rm NNLO}(M_{\rm
Z})=0.1143\pm 0.0014 ({\rm exp})$ with a guess $\alpha_s^{\rm NNNLO}(M_{\rm
Z})\sim 0.113$.
