  A Berkovits type action for pure spinors in even dimensions is considered.
The equations of motion for pure spinors are investigated by using explicit
parameterizations which solve the pure spinor constraints.
  For general interactions, the equations of motions are shown to be modified
from the naive ones. The extra terms contain a particular projector.
  If the interactions are restricted to the ``ghost number'' u(1) and the
Lorentz so(p,q) current couplings, the action has a large ``gauge symmetry''.
In this case, in some ``gauges'', the extra terms vanish and the equations of
motion for the pure spinors retain the naive form even if the pure spinor
constraints are taken into account.
