4.2.3.117	Mg2+	or Mn2+, required. Mg2+ is preferred over Mn2+	
4.2.3.117	Mg2+	required, Mg2+ is the preferred divalent cation	
4.2.3.117	Mn2+	or Mn2+, required. Mg2+ is preferred over Mn2+, Mn2+ shows 60-70% of the activity with Mg2+	
4.2.3.117	Mn2+	low activity