The analysis of complex mechanisms

Many enzyme-catalyzed reactions are consistent with a modified version of the Michaelis-Menten mechanism, in which the release of product from the ES complex is also reversible with the step 

Equation 8.4a tells us that the reaction rate depends on the concentration of product. However, at the early stages of the reaction, when [S] = [S]o [P], terms containing [P] can be ignored and it is easy to show that eqn 8.4a reduces to eqn 8.1. 

The simple mechanism described in the previous section is oniy a starting point to account for the full range of enzyme-controlled reactions, we need to consider more involved mechanisms. 

Many enzymes can generate several intermediates as they process a substrate into one or more products. An example is the enzyme chymotrypsin, which we treat in detail in Case study 8.1. Other enzymes act on multiple substrates. An excunple is hexokinase, which catalyzes the reaction between ATP cuid glucose (the two substrates of the enzyme), the first step of glycolysis (Section 4.8). The same strategies developed in Section 8.1 Ccui be used to deal with such complex reaction schemes, and we shall focus on reactions involving two substrates. 

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A rate-determining process for the formation of important free radicals should be identified in the analysis of complex mechanisms of reactive plasmas. 

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