Under specific reaction types overall

For the purpose of the present discussion the term transient kinetics is applied to the time course of a reaction from the moment when enzyme and substrate are mixed, t=0, until either a steady state or equilibrium is established. The difference between the kinetic problems discussed in section 3.3 and in the present section is, respectively, the presence of catalytic as distinct from catalytic concentrations of enzyme. Here we are concerned with the stoichiometry of enzyme states. Transient kinetic experiments with enzymes can be divided into two types. The first of these (multiple turnover) is carried out under the condition that the initial concentrations of substrate and enzyme are Cs(0) Ce(0) and c it) can, therefore, be regarded as constant throughout the course of the reaction until a steady state is attained. Alternatively, in a single turnover reaction, when Cs(0)reaction intermediates is observed until the overall process is essentially complete. These two possibilities will be illustrated with specific examples. In connection with a discussion of the approach to the steady state, in section 3.3 it was emphasized that, at t = 0, the concentrations of the intermediates, enzyme-substrate and enzyme-product complexes, are zero and, therefore, the rate of product formation is also zero. Under the experimental conditions used for steady state rate measurements and for enzyme assays, the first few seconds after the initiation of a reaction are ignored. However, when the experimental techniques and interpretation discussed below are used, events during the first few milliseconds of a reaction can be analysed and provide important information. With suitable monitors it is possible to follow the formation and decay of enzyme complexes with substrates and... 

Substrate-specific BCOs, when reacting with substrates under natural conditions, follow Michaelis-Menten kinetics with reasonably high catalytic activity [42]. The substrate-enzyme reaction, or reduction of the Cu " sites, is the rate-determining step for the overall enzymatic reaction [37], whereas the oxygen reduction reaction (ORR) occurs much more rapidly. This type of enzymatic reaction would not participate in any electrocatalytic electron transfer unless the substrate is actually the electrode. Therefore, the goal for BFCs is to configure the enzyme by a method that allows the electrode to assume the role of substrate so that the electrons can travel through an external circuit. 

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