Cytochrome c oxidase subunit 2
Cytochrome c oxidase II is a protein in eukaryotes that is encoded by the MT-CO2 gene. Cytochrome c oxidase subunit II, abbreviated COXII, COX2, COII, or MT-CO2, is the second subunit of cytochrome c oxidase.
Source: Wikipedia — Cytochrome c oxidase subunit 2 (CC BY-SA 4.0)