Active sites in enzymes

Finally, we come to enzyme models. D. W. Griffiths and M. L. Bender describe the remarkable catalytic property of certain cycloamyloses which act through formation of inclusion complexes, and in this respect recall the clefts containing the active sites in enzymes such as lysozyme and papain. 

Circular dichroism Secondary structure of proteins, interaction between ligands and proteins, binding of metals at active sites in enzymes 1 )... 

A third reason is that a sufficient length of polypeptide is needed to enforce the shape of a protein, and particularly the precise stereoelectronic architecture of its active site. In enzymes, for example, this allows coupled vibrations and energized motions that contribute to catalytic mechanisms and an exquisitely fine-tuned stabilization of transition states (Kraut, 1988 Havsteen, 1989 Retey, 1990 Knowles, 1991 Tonge and Carey, 1992 Williams, 1993). 

Future work will naturally extend to study complex systems, such as hydration dynamics around different secondary-structure globular proteins at interfaces of protein-DNA, RNA, or protein complexes and at the active sites in enzymes. On the theoretical side, significant efforts are needed to solve the serious discrepancies of total solvation energy, ultrafast inertial motion, as well as protein flexibility and induced solvation. 

Requirements of Active Sites in Enzymes Carboxypeptidase, which sequentially removes carboxyl-terminal amino acid residues from its peptide substrates, is a single polypeptide of 307 amino acids. The two essential catalytic groups in the active site are furnished by Arg145 and Glu270. 

Mo(V) complex disproportionates as it dissociates to produce mononuclear Mo (IV) and Mo (VI). As Mo (IV) and Mo (VI) are directly interconvertible by an oxo transfer reaction, they are viable participants in catalytic cycles. A dinuclear Mo(V) species of this nature can thus supply either the oxidizing or reducing member of this couple and presents a mechanism by which molybdenum enzymes can channel reducing or oxidizing power. Several inorganic reactions have recently been explained using this scheme (80, 81). To date, however, Reaction 12 only applies when the ligand is a dithiocarbamate or dithiophosphate. Nevertheless, were there known dinuclear active sites in enzymes, this would be an important mechanism to consider. 

Characterize the structure and dynamics of active sites in enzymes and the correlated motions of secondary and tertiary structures. Measure half-lifetimes of individual steps of electron- and ion-transport during catalytic cycles. Synthesize ligands for metal centers and functionalize inorganic pores to attain enzyme-like activity and selectivity with inorganic-like robustness. 

Condensed N-heterocycles as dimensional probes of active sites in enzymes 86T1917. 

Requirements of Active Sites in Enzymes Carboxy-peptidase, which sequentially removes carboxyl-terminal... 

The similarity of this equation to Eq. (6.26) should be noted, since these equations ULustrate the similarity between reactions of adsorbed gases on solids and substrates bound to enzyme active sites in enzyme catalysis. 

Why do metals make for such effective active sites in enzyme catalysis ... 

Described in this article are four zinc enzymes and their representative functional models. Although the three-dimensional structures of many zinc enzymes were determined in the last decade, the dynamics and mechanisms of the catalytic process of the zinc enzyme are complicated and still not fully understood. Therefore, to resolve the nature of the active site in enzymes it is necessary to prepare an appropriate model complex. From a series of studies by functional models, it is found that the of the coordinated water controlled by the ligand properties and the coordination mode of the substrate are essential to obtain catalytic activity for zinc enzymes. However, no functional models exhibit the activity observed by the native enzyme under physiological conditions. Thus, the goal that remains is to elucidate the significant difference in catalytic activity between the zinc enzymes and these models and then create a supramolecular composite of an artificial zinc enzyme that demonstrates the excellent catalytic function. 

The active sites in enzymes are transition metal (TM) complexes which are responsible for the catalytic activity. Such complexes are surrounded by a protein mantle, which is rigid or flexible and is responsible for the regioselectivity. They operate via the key-lock principle (equation I). 

Photoaffinity labeling—a well known technique for studying active sites in enzymes—has attracted considerable attention as a tool to ascertain structure-function relationships in more complex biological structures, such as ribosomal binding sites or membrane receptor sites. ... 

The problem of embedding is not limited to zeolitic active sites. It has also been discussed in connection with the determination of active sites in enzymes. Here a method combining quantum Mechanics (QM) with classical Molecular Dynamics (MD) is used. This (QM/MD) method is based on a partition of... 

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