the pattern of intermediate products generated during the action of chicken erythrocyte topoisomerase on a supercoiled closed circular dna substrate has been examined quantitatively and has been shown to be consistent with a mechanism in which the enzyme closes its substrate dna molecular after the removal of each superhelical turn and in which dissociation of the enzyme substrate complex may , but does not necessarily , occur after each cycle of the reaction .
C0012925
circular dna
C0012854
dna