Predicting the activity of enzymes upon phosphorylation/ dephosphorylation

A reversible covalent modification by Phosphorylation/Dephosphorylation of the key regulatory enzymes of various metabolic pathways is a well-established mechanism to regulate their activities soas to maintain body homeostasis. At the molecular level this reversible covalent modification is known to occur by a mechanism involving cAMP as a second messenger and cascade of enzymes. Some enzymes are known to become active while others inactive upon Phosphorylation or Dephosphorylation.The question that naturally arises is whether the selection of an enzyme to become either active or inactive upon hosphorylation or Dephosphorylation is a random phenomenon or is based upon some scientific evolutionary logic? A hypothesis has been proposed which based upon well established facts can help us to very easily predict which enzyme should become active or inactive upon Phosphorylation or Dephosphorylation.