what is the co factor of restriction endonulease EcoRV that

what is the co factor of restriction endonulease EcoRV that activiates water for nuceophilic attack?

Solution

Magnesium ion (Mg2+).

The magnesium ion holds a water molecule in a position from which the water molecule can attack the phosphoryl group and, in conjunction with the aspartate residues, helps polarize the water molecule toward deprotonation.Additional studies have revealed that a second magnesium ion must be present in an adjacent site for EcoRV endonuclease to cleave its substrate.