This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Glycolysis, Subject name: Biochemistry
In Glycolysis which of the ion is most impoant? 
Select and explain. 
A. Zn, B. Mg, C. Cu, D. Ca
B: Mg
Answer: B: Mg 
Explanation: Mg is most impoant for kinases. There are four kinases hexokinase, phospho fructo kinase, phospho glycerate kinase pyruvate kinase But pyruvate kinase requires K>Mg