PARTS OF PROTONS. “Protons are composite particles composed of three valence quarks: two up quarks of charge +2/3 e and one down quark of charge −1/3 e. The rest masses of quarks contribute only about 1% of a proton’s mass. The remainder of a proton’s mass is due to quantum chromodynamics binding energy, which includes the kinetic energy of the quarks and the energy of the gluon fields that bind the quarks together.”
https://en.m.wikipedia.org/wiki/Proton