Deoxyribonuclease I gene is approximately 3.2 kb long with 9 exons separated by 8 introns. In the form of a bovine pancreatic enzyme preparation, it occupies an important place in the history of protein chemistry and enzymology: it was the first enzyme to be recognized as specific for DNA; it was the first DNase to be crystallized; and it was the first DNase for which a specific protein inhibitor was characterized. DNase I is a Ca2+ and Mg2+ dependant endonuclease. DNase I is synthesized in