Restriction Endonuclease

Abstract

Deoxyribonucleic acid is one of the most interesting and also the most complex of all biological macromolecules. Paradoxically, this complexity arises from the simplicity of its basic subunit structure. A large eukaryotic chromosome probably contains a single chain of DNA with a molecular weight in excess of 10¹¹ daltons and is composed of a linear permutation of the four basic deoxyribonucleotides. Until recently, this fact posed considerable problems for the biochemist interested in isolating specific fragments of chromosomes as the methods available were nonspecific in nature. This is no longer so; the discovery of site specific endodeoxyribonucleases (restriction endo-nucleases) has opened new routes to the analysis of DNA structure and function and promises a revolution in molecular biology. A new field of genetic engineering is already being pioneered, and significant advances in many areas have been facilitated by the availability of these enzymes.