Do enzymes lower the activation energy of a reaction?
That's a little tricky - they reduce the energy to accomplish a specific reaction by changing the pathway.
It's not that they can simply "reduce" the energy needed to start a reaction between two compounds. They act as intermediaries or pathways that get the compounds together with less energy than would be required without the enzyme interaction.
So, the net observed effect is that they have reduce the "activation energy" when observe thermodynamically. But they did not change the original pathway energy requirements. It is like the difference between hauling a load over a mountain. The "product" is the delivery on the other side. The "pathway" can be directly over the top of the mountain (high energy) or along a path through a lower pass that gets the job done with less expended energy.