Final answer:
The mutant enzyme with increased affinity would likely have a decreased KM value. A lower KM value indicates a stronger binding between the enzyme and substrate.
Step-by-step explanation:
The mutant version of the enzyme that increases its affinity or ability to bind its substrate would likely have a decreased KM. KM, or the Michaelis constant, is a measure of the substrate concentration at which the reaction rate reaches half of its maximum velocity, Vmax. A lower KM value indicates a stronger binding between the enzyme and substrate. Therefore, if the mutant version of the enzyme has an increased affinity for its substrate, it would result in a decreased KM value.