We report on the yield of protons and antiprotons, as a function of centrality and transverse momentum, in Au+Au collisions at    √^s_NN =200 GeV measured at midrapidity by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider. In central collisions at intermediate transverse momenta (1:5<p_r<4:5 GeV/c) a significant fraction of all produced particles are protons and antiprotons. They show a centrality-scaling behavior different from that of pions. The p= and p= ratios are enhanced compared to peripheral Au+Au,p+p,and e⁺ e^- collisions. This enhancement is limited to pr<5 GeV/c as deduced from the ratio of charged hadrons to 0measured in the range 1:5<pr<9 GeV/c.