Some metal ions can improve the activity of enzymes, that is, enzyme activators, such as potassium ions, sodium ions, magnesium ions, zinc ions and ferrous ions.

According to the classification of enzyme composition, enzymes can be divided into simple enzymes and combined enzymes. Combined enzymes are composed of de-coenzyme and cofactors, which include coenzyme, cofactors and metal ions, and metal ions play a role in them.