  It is shown, that if the pentaquark $\Theta^+ = uudd\bar{s}$ baryon can be
represented by the local quark current $\eta_{\Theta}$, its decay $\Theta^+ \to
n K^+ (p K^0)$ is forbidden in the limit of chirality conservation. The
$\Theta^+$decay width $\Gamma$ is proportional to $\alpha^2_s < 0 | \bar{q} q |
0 >^2$, where $<0 | \bar{q} q | 0 >$, $q = u,d,s$ is quark condensate, and,
therefore, is strongly suppressed. Also the polarization operator of the
pentaquark current with isospin 1 is calculated using the operator product
expansion and estimation for it mass is obtained .
