1 Introduction Enzyme turnover number ( k cat $k_{\text{cat}}$ ) is a key kinetic parameter that quantifies the catalytic activity of an enzyme, representing the maximum number of substrate molecules converted to products per active site per unit time [1]. Accurate prediction of k cat $k_{\text{cat}}$ values and rational ranking of the catalytic activity of enzyme mutants are critical for advancing enzyme engineering, synthetic biology, and industrial biocatalysis [2-4].
