Final answer:
The enzyme that facilitates the movement of a transposon from one DNA site to another is called transposase, which is encoded by the transposon itself.
Step-by-step explanation:
The enzyme that catalyzes the excision of a transposon from a donor DNA site and subsequent insertion at a target DNA site is called transposase. This enzyme is encoded by the transposon itself. Transposase orchestrates the movement of the transposon through a cut-and-paste mechanism or a replicative transposition process. During this process, transposase performs a precise hydrolytic attack at the donor site to excise the transposon, and then mediates its insertion into a new target DNA site by catalyzing the joining of the transposon's 3'OH ends with the 5'OH ends of the target DNA. This action produces direct repeats of host cell genomic DNA at the insertion site. The final ligation step completes the transposition.