Apart from their charge, electrons and positrons have exactly the same quantum mechanical properties. Protons and electrons, however, are different particles entirely .Apart from their charge, they have different masses. Protons are composed of quarks and gluons, while electrons have no internal structure. We can, however, manufacture a proton and an anti-proton. When these identical, but opposite charged, particles collide they DO annihilate each other just like the electron and the anti-electron ( positron) do.