The evolution of product formation was linearly dependent on time during the first minutes of the reaction. From the Michaelis-Menten kinetic model, constants, Km, of pepsin and trypsin were obtained and maximal rates, Vmax, were calculated by expressing 1/Vi versus 1/[S]. The different results obtained for both enzymes are summarized in Table 3.
Vmax and Km values of immobilized enzyme were slightly higher than those of the free enzyme in solution. These results were most likely due to the following factors. The immobilized enzymes did not have the same accessibility to the substrates than the soluble enzymes. This could be explained by the fact that a higher concentration of substrate was needed to enhance the collisions with the immobilized enzyme as compared to the same amount of soluble enzyme, and resulting in an increased Km. In the case of pepsin, adsorption of a substrate such as hemoglobin could also be responsible for the increase in Vmax as compared to the free enzyme.
Table 3. Values of Michaelis-Menton constant, Km, and maximum reaction rate, Vmax
In solution On cotton fibers In solution On cotton fibers
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