MOXD1 is a 613 amino acid single-pass type I membrane protein of the Endoplasmic reticulum that belongs to the copper type II ascorbate-dependent monooxygenase family. Existing as two alternatively spliced isoforms, MOXD1 is expressed in adult spinal cord, adrenal gland, brain, testis, uterus, lung and kidney, as well as fetal liver and brain. MOXD1 is upregulated during replicative senescence in primary fibroblast and umbilical vein endothelial cell cultures, and uses two copper ions per subunit as a cofactor. MOXD1 contains one DOMON domain, undergoes post-translational N-glycosylation and is encoded by a gene that maps to human chromosome 6. Chromosome 6 contains 170 million base pairs, comprises nearly 6% of the human genome and is associated with early onset intestinal cancer, Porphyria cutanea tarda, Parkinson's disease and Stickler syndrome.