This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
In which of the following reactions is Magnesium required as an activator? 
Select and explain. 
A. ATPase, B. Aldolase, C. Dismutase, D. Phosphatase
D: Phosphatase
Answer: D: Phosphatase 
Explanation: Magnesium is the activator of many enzymes requiring ATP. The enzymes requiring magnesium are alkaline phosphates, hexokinase, fructokinase, phosphofructokinase, phosphopyruvic and acetyl trans phosphorylases. It is also required for the activation of adenyl cyclase systems and for the activity of cyclic AMP dependent kinases like those involved in phosphorylation of nucleotides and glycogen metabolism. Ref: Textbook of Biochemistry and Human Biology By L. M. Srivastava, 3rd Edition, Page 583 ; Textbook of Biochemistry By D M Vasudevan, 3rd Edition, Pages 288-9