Enzyme complexes systems

Osmo- and ion-regulation play a pivotal role in the cellular metabolism of an animal and its imbalance leads to changes in various physiological and biochemical functions (Moorthy et al., 1984). For maintenance of osmo-concentration of body fluids, sodium, potassium and calcium ions are essential and their role in this aspect has been well demonstrated in molluscs (Schoffeniels and Gilles, 1972). The ATPase enzyme complex system helps in the uptake of such vital ions from the external medium into the body fluids. 

An immobilized enzyme-carrier complex is a special case that can employ the methodology developed for evaluation of a heterogeneous cat ytic system. The enzyme complex also has external diffusional effects, pore diffusional effects, and an effectiveness factor. When carried out in aqueous solutions, heat transfer is usually good, and it is safe to assume that isothermal conditions prevail for an immobihzed enzyme complex. 

The above enantioselectivities are obviously complex functions of many factors, perhaps even more complex than in natural enzymes. Complexity is partly due to the present co-micellar system in which it is difficult to analyze separately the interaction of the substrate with the achiral micelle, and that of the substrate with the catalyst complex. 

The use of a catalyst with oxidase enzyme is an example of the use of a combined enzyme system, which illustrates the wide potential offered by multi-enzyme electrode systems. Various enzymes can be arranged to work sequentially to transform quite complex substances and eventually produce a measurable concentration-dependent change, which is detected by the output signal and recorded for analysis. 

The high catalytic activity of enzymes has a number of sources. Every enzyme has a particular active site configured so as to secure intimate contact with the substrate molecule (a strictly defined mutual orientation in space, a coordination of the electronic states, etc.). This results in the formation of highly reactive substrate-enzyme complexes. The influence of tfie individual enzymes also rests on the fact that they act as electron shuttles between adjacent redox systems. In biological systems one often sees multienzyme systems for chains of consecutive steps. These systems are usually built into the membranes, which secures geometric proximity of any two neighboring active sites and transfer of the product of one step to the enzyme catalyzing the next step. 

This variant can be derived from the Lineweaver-Burk form in eq. (39.115) by multiplying both sides by X. From a statistical point of view, it does not seem to have an advantage over the Lineweaver-Burk form [14]. The latter variant, however, can be more easily extended to more complex systems of substrate-enzyme reactions, as will be shown below. 

To summarize these data it appears that this enzyme system involves CH3-transfer to a Co(I)-enzyme to give a methylcorrinoid-enzyme complex. Subsequent transfer of CH3 from this methylcorrinoid-enzyme... 

The FePcY-PDMS supramolecular catalyst resembles the architecture of natural enzymes. In this system the PDMS membrane takes over the role of the phospholipid double layer likewise, the zeolite imitates the protein and the FePc complex the Fe-protoporphyrin. Zeolite-encaged Cu-histidine complexes were also studied as mimics of natural Cu-enzyme complexes.173... 

---