The rate limiting step in the enzyme catalyzed transformation of substrate S into product P is the breakdown of the ES complex:
Since the ES concentration is not easily measured experimentally, Leonor Michaelis and Maud Menten have given an alternative expression for the determination of the rate of such enzymatic reactions: where KM, the Michaelis constant is defined as:
Several algebraic transformations to a linear form have been proposed for this equation which are more useful in the analysis of the experimental data: Lineweaver-Burk, Eadie and Dixon.
Given the following data for the hydrolysis of sucrose by the enzyme invertase, find which equation has the best correlation coefficient, determine the Michaelis constant and kb - the maximum turnover number:
In the Dixon expression, which has the best correlation, the substrate concentration [S] is correlated to the ratio of the substrate concentration [S] to the rate k. The maximum turnover number is the reciprocal of the slope, and the Michaelis constant is the product of the intercept with the maximum turnover number.