The Mg2+ ion has the highest charge density of any biologically relevant ion. This is due to its small radius (0.6 Å).
It is used as the center of many biological coordination compounds and thus participates in many reactions.
Magnesium ions participate in:
- Stabilisation of membranes
- Complexation of phosphates and nucleotides
- Dephosphorylation (Phosphatase)
- Muscle contraction