Enzymes, active conformation fluctuations

The insertion of a protein within a membrane not only stabilizes the optimal conformation for the enzyme activity, but also limits the possible conformations it may undergo. Thus, assuming a mechanism for the enzymatic activity, where the underlying assumption is that the conformational fluctuation controls the chemical reaction, a decrease in the number of degrees of freedom for the enzyme increases its probability for... 

Currently suggested models for tunneling increasingly invoke protein dynamics . These models envision either a series of conformational fluctuations that lead to a suitable tunneling configuration ( passive dynamics ) or a more active role for the enzyme motions ( active dynamics or gating ).64 On the model of... 

Enzyme activity is controlled by changes in the conformation of the molecules, masking and unmasking of the active centers, the relative proportions of isozymes, substrate concentration, concentration of the end product, activators and inhibitors at the genetic level, activators and inhibitors at the functional level, hormones, coenzymes, fluctuations in pH and ionic strength of the medium, and many other factors. Of these other factors the most important are the velocity of synthesis and breakdown of enzymes, determining the enzyme concentration in the cytoplasm and other media of the organism. 

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