Cytochrome c oxidase (COX), the terminal enzyme of the mitochondrial respiratory chain, catalyzes the electron transfer from reduced cytochrome c to oxygen. It is a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes. The mitochondrially-encoded subunits function in electron transfer, and the nuclear-encoded subunits may be involved in the regulation and assembly of the complex. This nuclear gene encodes isoform 2 of subunit IV. Isoform 1 of subunit IV is encoded by a different gene, however, the two genes show a similar structural organization. Subunit IV is the largest nuclear encoded subunit which plays a pivotal role in COX regulation.COX4I2 (Cytochrome C Oxidase Subunit 4I2) is a Protein Coding gene. Diseases associated with COX4I2 include Exocrine Pancreatic Insufficiency, Dyserythropoietic Anemia, And Calvarial Hyperostosis and Calvarial Hyperostosis. Among its related pathways are Respiratory electron transport, ATP synthesis by chemiosmotic coupling, and heat production by uncoupling proteins. and AMPK Enzyme Complex Pathway. GO annotations related to this gene include cytochrome-c oxidase activity. An important paralog of this gene is COX4I1.