  We report the results from an ASCA observation of the high-luminosity,
radio-loud quasar PKS 0637-752 (redshift 0.654), covering the 0.8-15 keV band
in the quasar-frame. We find the source to have a luminosity ~10^46 erg/s in
the 2-10 keV band, a factor of ~3 lower than during a previous GINGA
observation. The continuum appears to be well modeled by a simple power-law
with a photon index of 1.64 +/- 0.07, with no evidence for absorption by
material intrinsic to the quasar, or Fe-K emission (with an equivalent width <
80 eV at 90% confidence). However we do find evidence for a narrow emission
line at an energy 1.60 +/- 0.07 keV and equivalent width 59 [+38,-34] eV (both
in the quasar frame). Line emission at these energies has not been observed in
any other active galaxy or quasar to date. We reject the possibility that this
line is the result of instrumental artifacts, and briefly explore possible
identifications.
