Glad you are doing some research on what you are trying to take. Diabetes is one condition that most definitely throws a huge variable into the equation that must be factored in - especially when someone is taking insulin. Diabetes is a metabolic disorder, so enzymes or cofactors that behave as enzymes must be approached with caution to make sure one does not cause other metabolic issues in an attempt to improve either the blood sugar dysregulation or some other condition. Supplements are not as dangerous as pharmaceuticals, but they are also not inert - they do have actions that affect pathways in the body.

These books should help you navigate what enzymes do what. I like the first book I listed. It was the one that I started with when I began my medical career and was my go to handbook. The people that published that book had an earlier book on natural remedies that was also very good. Both are comprehensive and contain lots of information. The subject of enzyme therapy has fascinated me ever since college. I am also a big proponent of complimentary medicine. I am sure you will find the information useful.