  Study of the MSSM in large tan$\beta$ regime has to include correlations
between the constraints presented by the low energy values of the b quark mass
and $BR(b\to s\gamma)$. Both quantities receive SUSY contributions enhanced by
tan$\beta$ and have a major impact on the MSSM analysis. Here we summarize the
results of such a study constrained by minimal SO(10) unification. We show the
best fits, in the $(m_0,M_{1/2})$ plane, obtained in the global analysis
spanned over the gauge, Yukawa and SUSY parameter space at the unification
scale. Two distinct fits describe the available low-energy data very well. The
fits differ by the overall sign of the $b\to s\gamma$ decay amplitude. We
conclude that an attractive SO(10)-derived regime of the MSSM remains a viable
option.
