This study comes up with alternative definitions, explanations, and methods of calculation. While the conceptual definition given by Kozuch et al. supports Eq. ( ) if division by time in seconds is done, the mathematical aspect does not give support. The conceptual definition is: From a mathematical perspective, the TOF (like any other ratebased quantity) must be defined as the derivative of the number of turnovers with respect to time . Besides, the TOF is, according to Boudart , simply defined as the number of revolutions of the catalytic cycle per unit time, generally the second. Rather, the TOF is a function of the catalytic cycle per unit time in seconds. If kcat is equivalent to TOF, there cannot be any single turnover event with any concentration of the enzyme considering the Preprint submitted to ChemRxiv, Jun 05, 2023 fact that kcat times time is ≫ 1. This is applicable to vi/[ET] times time (vi can be the lowest initial rate for the lowest concentration of the substrate).