The solution to DNA's topological problems comes in the form of enzymes called topoisomerases that serve as "swivels" and allow the molecule to perform its requisite acrobatics. Type I topoisomerase breaks one strand of the DNA, and Type II topoisomerase breaks both strands of the helix.
Since 1980 there has been a notable increase in research on topoisomerases. The number of 1988 papers indexed in the Institute for Scientific Information's on-line database SciSearch having the word topoisomerase and variants in their titles was 10 times the number indexed in 1980 (see accompanying graph). James C. Wang, Harvard University, a key player in this field who first identified the enzyme in 1971, confirmed that the 1980s has been a period of rapid growth in topoisomerase research. He noted, however, that The Scientist's graph might slightly underrepresent the amount of work produced in 1980-1982, since the term topoisomerase was not coined until ...
