What does the law of superposition state

In physics and systems theory, the superposition principle,[1] also known as superposition property, states that, for all linear systems, the net response at a given place and time caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually. So that if input A produces response X and input B produces response Y then input (A + B) produces response (X + Y).

The homogeneity and additivity properties together are called the superposition principle. A linear function is one that satisfies the properties of superposition.

not sure if this what   you'r looking for would be percent composition

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products