Final answer:
Topoisomerases are the enzymes that remove supercoiling in replicating DNA ahead of the replication fork, preventing DNA from becoming too tightly wound and potentially damaged.
Step-by-step explanation:
The enzyme responsible for removing supercoiling in replicating DNA ahead of the replication fork is topoisomerases. These enzymes alleviate the tension caused by the unwinding of DNA by cutting one or both strands of the DNA molecule allowing it to unwind and then resealing the cuts.
This action prevents the DNA from becoming too tightly coiled or supercoiled which can stall replication and lead to DNA damage.