Mechanism of Enzymatic Catalysis

The overall process of enzyme catalysis may be represented by Equation 2.8, where E, S and P represent enzyme, substrate and product, respectively. Note that the enzyme is regenerated after the reaction, as required in a catalytic process. 

The quantities and Vmaxare important parameters that can be used to characterise and understand enzymatic reactivity. The value is the Michaelis constant which is defined as the substrate concen- 

There are exceptions to Michaelis-Menten behaviour. For example allosteric enzymes which instead of a hyperbolic curve in a V versus [S] graph yield a sigmoidal plot (the behaviour is rather like non-catalytic allosteric proteins, such as haemoglobin. Section 2.5. This type of curve can indicate cooperative binding of the substrate to the enzyme. We have discussed cooperativity in Section 1.5 (see also Section 10.4.3). In addition, regulatory molecules can further alter the activity of allosteric enzymes. 

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Fray, P. A. (2001) Radical mechanism of enzymatic catalysis, Annu. Rev. Biochem. 70, 121-148. 

Understanding molecular mechanisms of enzymatic catalysis depends on a detailed knowledge of the structural framework within which substrate recognition and catalysis occur. Determination of the X-ray crystal structure of S. cerevisiae flavocytochrome 62 by Mathews and colleagues (23-25), coupled with the availability of the complete amino acid sequence (26, 27), has allowed detailed analysis of substrate recognition and catalysis in this enzyme. 

Frey PA (2001) Radical mechanisms of enzymatic catalysis. Annual Reviews of Biochemistry 70, 121 8. 

Biochemical Connections Is the following statement true or false Why The mechanisms of enzymatic catalysis have nothing in common with those encountered in organic chemistry. ... 

Transient-state kinetic approach to mechanisms of enzymatic catalysis 05ACR157. 

Work in the area of micellar catalysis in both aqueous and nonaqueous solvent systems is certain to continue to grow in importance as a tool for better understanding the chemistry and mechanics of enzymatic catalysis, as a probe for studying the mechanistic aspects of many reactions, and as a route to improved yields in reactions of academic interest. Of more practical significance, however, may be the expanding use of micellar catalysis in industrial applications as a method for obtaining maximum production with minimum input of time, energy, and materials. 

Quantum chemical modelling in the research of molecular mechanisms of enzymatic catalysis 12UK1011. 

Chemical Modification of Lipases. The chemical modification of enzymes involving the formation of covalent bonds are a major tool for elucidating the mechanisms of enzymatic catalysis [496 98]. These investigations were aimed primarily at defining those amino acids which participate in catalysis and those which are important in substrate binding. Furthermore, the properties of the enzyme such as solubility, pH optimum, inhibition patterns, and the relative reactivity towards different substrates - the specificity - can be varied by chemical modification. More recently, it was also shown that the enantioselectivity of a lipase may also be improved by covalent modification [499-501] (compare Scheme 2.72 and Table 2.2). 

Enzymatic catalysis has fascinated biochemists and physical and organic chemists alike for several generations. By their specificity and their catalytic efficiency enzymes are even today the paragons of homogeneous catalysis, especially when catalysis in aqueous media at neutral pH values is concerned. Thus, the mechanism of enzymatic catalysis is the subject of more intense study than ever before. 

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