Homogeneous Enzymatic Catalysis

The first expression is used in heterogeneous catalysis, the second form is more common in homogeneous and bio-enzymatic catalysis, with the useful constant... 

The Ping-Pong Mechanism in Homogeneous Enzymatic Catalysis... 

Special attention is given to the integration of biocatalysis with chemocatalysis, i.e., the combined use of enzymatic with homogeneous and/or heterogeneous catalysis in cascade conversions. The complementary strength of these forms of catalysis offers novel opportunities for multi-step conversions in concert for the production of speciality chemicals and food ingredients. In particular, multi-catalytic process options for the conversion of renewable feedstock into chemicals will be discussed on the basis of several carbohydrate cascade processes that are beneficial for the environment. 

The basic concept is the intuition that, whether homogeneous or heterogeneous, catalysis is primarily a process controlled by a molecular phenomenon since it implies the catalyzed transformation of molecules into other molecules. It follows that on the surface of metals or metal oxides, sulfides, carbides, nitrides usually involved as heterogeneous catalysts, the relevant surface species and the mechanism of their mutual reactions must be of molecular character, as occurs in homogeneous or enzymatic catalysis. 

Developing the ideas of the enzymatic catalysis mechanism, Poltorak [1] formulated a scientific statement about the meeting of chemical mechanisms of homogeneous, heterogeneous and enzymatic catalysis in the framework of the concept of a linear bond redistribution chain... 

In the realm of homogeneous catalysis we often encounter examples of acid- and base-catalyzed hydration-dehydration and hydrolysis, metal-catalyzed hydrolysis and autoxidation, photocatalytic oxidation and reduction, metal-catalyzed electron transfer, acid-catalyzed decarboxylation, photocatalytic decarboxylation, metal-catalyzed free-radical chain reactions, acid-catalyzed nucleophilic substitutions, and enzymatic catalysis. 

In the following text (Chapters 5 and 6) we will demonstrate how eq. (4.88) can be applied to specific cases of homogeneous and enzymatic catalysis. 

---