Magnesium ion influences enzyme activity by binding to the active site of the enzyme or the substrate. This binding can induce a conformational change in the enzyme, enhancing its ability to catalyze the reaction. For example, in the [enzyme hexokinase](https://en.wikipedia.org/wiki/Hexokinase), Mg2+ binds to ATP and facilitates the transfer of the phosphate group to glucose, initiating glycolysis.
