Final answer:
Restriction endonucleases are enzymes that cleave dsDNA at specific sequences. If they were faster with turnover numbers similar to carbonic anhydrase, it would be beneficial to host cells as they would be able to more efficiently defend against foreign DNA.
Step-by-step explanation:
Restriction endonucleases are enzymes that cleave dsDNA at specific sequences with high specificity. They are used by molecular biologists to cleave plasmid or synthesized DNA during cloning. The turnover number of restriction endonucleases is typically 1 s-1, making them relatively slow enzymes. However, if restriction endonucleases were faster with turnover numbers similar to carbonic anhydrase (106 s-1), they would act faster than methylases.
The increased rate of fast restriction endonucleases would be beneficial to host cells, assuming that the fast enzymes have similar levels of specificity. With faster cleavage, the host cells would be able to more efficiently defend against foreign DNA by cleaving it quickly and accurately. This would enhance the cell's ability to protect its own DNA from potentially harmful intruders.