Textbook literature on the kinetic evaluation of enzyme inhibitors contains certain simple algebraic formulas (see below) that can be used to determine the number of microscopic inhibition steps and the values of relevant kinetic constants from k obs data. Those formulas are applicable to simplified experimental conditions without the involvement of tight-binding, i.e., without inhibitor depletion . An important complication arises when the inhibition assay is in fact conducted under tight-binding experimental conditions, where at least some inhibitor concentrations already causing a measurable inhibitory effect are comparable with the enzyme concentration.