Oxidative phosphorylation. Definition. noun. A metabolic pathway that generates ATP from ADP through phosphorylation that derives the energy from the oxidation of nutrients. Supplement. Oxidative phosphorylation is an enzymatic process that occurs in both prokaryotes and eukaryotes.xidative phosphorylation. Definition. noun. A metabolic pathway that generates ATP from ADP through phosphorylation that derives the energy from the oxidation of nutrients. Supplement. Oxidative phosphorylation is an enzymatic process that occurs in both prokaryotes and eukaryotes.