Final answer:
Topoisomerase is the enzyme that regulates the degree of supercoiling by breaking and reforming DNA's nucleotide base pairs or phosphate backbone. It relieves the pressure that results from supercoiling by controlling unwinding of the double helix.
Step-by-step explanation:
Topoisomerase is the enzyme that regulates the degree of supercoiling by nicking DNA.
It relieves the pressure that results from supercoiling by breaking and reforming DNA's nucleotide base pairs or phosphate backbone ahead of the replication fork.
The topoisomerase enzymes bind to DNA, catalyze hydrolysis of phosphodiester bonds, control unwinding of the double helix, and catalyze the re-formation of the phosphodiester linkages.