@burcidi-- Enzymes are used in cancer research and I think allosteric enzymes are used a lot for anti-cancer drugs. I don't think that enzymes can stop cancer cells from dividing for now. We still have a lot to learn about enzymes, their activity is not always understood well or predicted. But allosteric enzymes can be used to change the metabolism of cancer cells and I think this is the only way in which they can be used in cancer treatment for now.
Penicilin is another drug where allosteric enzymes are used. Enzymes have already improved drugs and treatments despite ongoing research and lots of unknowns. I think things will only get better in the future. I really do believe that we will beat many illnesses one day and enzymes are going to be one of the things which helps us in doing this.