What is an enzyme and explain its mechanism of action

An enzyme is a protein that is used as a catalyst in a reaction within an organism. This is used in such a way that it lowers the energy requirement for a specific reaction to occur and this could either be a sigle enzyme for a single reaction or a string of sequential enzymes to produce variable transition states of substrates from the initial reactant to the final product. The enzymes "active site" allows for it to bind to the substrate(s) for the reaction. The active site is the area of the ezymes structure that interacts with the subtrates, which is thought of by 2 theories:Lock and Key: where there is a specific enzyme for each specific reaction. The enzyme will exist for 1 sole reaction of specific certain reactionInduced Fit: where the ezymes active site changes shape to stress reactant(s) bonds for the reaction to occur