EXOD1 is a 691 amino acid protein that contains one exonuclease domain, which catalyzes the hydrolysis of unpaired or mismatched nucleotides. EXOD1 acitivity is dependent on the binding of two magnesium ions per subunit. There are four isoforms of EXOD1 that are produced as a result of alternative splicing events. The gene encoding EXOD1 maps to human chromosome 16, which encodes over 900 genes and comprises nearly 3% of the human genome.