  In this paper, we endeavour to obtain a modified form of the Foldy-Wouthuysen
and Cini-Toushek transformations by resorting to the noncommutative nature of
space-time geometry, starting from the Klein-Gordon equation. Also, we obtain a
shift in the energy levels due to noncommutativity and from these results a
limit for the Lorentz factor in the ultra-relativistic case has been derived in
conformity with observations
