The underlying question is; what in the noodles or pasta are you aiming to improve?
Enzymes and gums are more different than apples and oranges. Guar gum in a noodle will impart more firmness and is sometimes used in dry noodles to make them less fragile, or susceptible to breakage. A place to start would be 0.01% and check with your gum supplier for recommendations on what you are trying to achieve.
For enzymes there could be a multitude of different things. It all depends on what your goals are. There are many different types of enzymes, and some are used in parts per million dosages (ppm).
If you can share more with us about your project, we would love to try and help.