  We analyse the proton and deutron data on spin dependent asymmetry
$A_1(x,Q^2)$ supposing the DIS structure functions $g_1(x,Q^2)$ and
$F_3(x,Q^2)$ have the similar $Q^2$-dependence. As a result, we have obtained
that $\Gamma_1^p - \Gamma_1^n = 0.190 \pm 0.038$ at $Q^2= 10 GeV^2$ and
$\Gamma_1^p - \Gamma_1^n = 0.165 \pm 0.026$ at $Q^2= 3 GeV^2$, what is in the
best agreement with the Bjorken sum rule predictions.
