Breaking [Formula Presented] by mixed noncommutativity

The mixed component of the noncommutative parameter (Formula presented) where (Formula presented) and M is an extra dimensional index, may violate four-dimensional (Formula presented) invariance. We calculate one- and two-loop induced couplings of (Formula presented) with the four-dimensional axial vector current and with the (Formula presented) odd (Formula presented) operators starting from five-dimensional Yukawa and (Formula presented) theories. The resulting bounds from clock comparison experiments place a stringent constraint on (Formula presented) (Formula presented) Orbifold projection and/or localization of fermions on a 3-brane lead to (Formula presented)-conserving physics, in which case the constraints on (Formula presented) are softened.