Enzyme complex, definition

CAS 9012-54-8 EINECS/ELINCS 232-734-4 Classification Enzyme complex Definition Derived from Aspergillus niger Properties Off-wh. powd. m.w. 31,000... 

Kinetic complexity definition, 43 Klinman s approach, 46 Kinetic isotope effects, 28 for 2,4,6-collidine, 31 a-secondary, 35 and coupled motion, 35, 40 in enzyme-catalyzed reactions, 35 as indicators of quantum tunneling, 70 in multistep enzymatic reactions, 44-45 normal temperature dependence, 37 Northrop notation, 45 Northrop s method of calculation, 55 rule of geometric mean, 36 secondary effects and transition state, 37 semiclassical treatment for hydrogen transfer,... 

Let us now consider in more detail the definitions of free energy related to enzyme reactions. Under steady state conditions, functioning enzyme complexes undergo cyclic transitions between a number of different states. These states can differ in the composition of a complex (enzyme molecule with ligands, substrates, products, low-molecular aflfectors, etc.), as well as in the conformations of an enzyme molecule. The complex s transitions are coupled with the chemical transformations of substrate molecules, the processes of association-dissociation of substrates and products, active transport of various substances, muscle contraction, etc. Most of these processes are of course associated with the energy transduction from one form to another. 

Trace metals including Mg, Zn, Cu, Mn, Fe, and Co are employed as cofactors in a number of enzymatic reactions. Indeed, for many enzymes the only cofactor is a metal ion. Two broad classes of metalutilizing enzymes are distinguishable by experimental means. These are the metalloenzymes where the metal is bound to the apoenzyme with sufficient strength to survive purification procedures and is present in a definite proportion to the protein, and the metal enzyme complexes where the metal, although easily dissociable, is required for full expression of enzyme activity. 

In this chapter, a short introduction to DFT and to its implementation in the so-called ab initio molecular dynamics (AIMD) method will be given first. Then, focusing mainly on our own work, applications of DFT to such fields as the definition of structure-activity relationships (SAR) of bioactive compounds, the interpretation of the mechanism of enzyme-catalyzed reactions, and the study of the physicochemical properties of transition metal complexes will be reviewed. Where possible, a case study will be examined, and other applications will be described in less detail. 

By definition, the observable rate of product formation (v) is proportional to the concentration of the enzyme substrate complex, ES ... 

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