  We present a generalization of the pioneering results obtained for single
K-shell photoionization of H-like ions by M. Stobbe [Ann. Phys. 7 (1930) 661]
to the case of the helium isoelectronic sequence. The total cross section of
the process is calculated, taking into account the correlation corrections to
first order of the perturbation theory with respect to the electron-electron
interaction. Predictions are made for the entire non-relativistic energy
domain. The phenomenon of dynamical suppression of correlation effects in the
ionization cross section is discussed.
