Question

How to find the number of sites in entire genome for a restriction enzyme?

Answer 1

Well you can usually calculate it yourself, take the length of the genome, and divide by how often an enzyme cuts on average. For example EcoRI cuts at a 6bp site, the frequency of cutting is 4^6, so it cuts every 4096bp on average, as it's sequnce will occur at random every 4096bp.

This does mean that in a genome of several billion such as humans, it will cut millions of times.