Why do weak bonds form between substrates and enzymes and not covalent bonds? What factors contribute to the formation of these bonds in the enzyme-substrate complex?

Question

Why do weak bonds form between substrates and enzymes and not covalent bonds?  What factors contribute to the formation of these bonds in the enzyme-substrate complex?

anonymous · Answer

because after the reaction occurs product must leave the active site.. if it was a covalent bond then it would be difficult to break the covalent bond....
presence of carbonyl group and amino gp is responsible for H-bonding....