  We have studied the production of single isolated prompt photons in high
energy proton-proton collisions at the RHIC ($\sqrt{s}$= 200 GeV) and the LHC
($\sqrt{s}$= 7 TeV) energies within the frame work of perturbative QCD upto
next-to leading order of strong coupling ($\alpha_s$). We have used five
different parameterizations of parton distribution function (PDF) starting from
the old CTEQ4M to the new CT10 distributions and compared our results with the
recent single prompt photon data from the PHENIX and the CMS collaborations.
The prompt photon cross-section is found to be described equally well by all
the PDF's within the experimental errors at the RHIC and the LHC energies. The
deviation in the prompt photon yield for different PDF sets is within $\pm$ 20%
when compared to CTEQ4M. The diphoton measurement could be a potential
candidate to constrain the gluon distribution inside the proton.
