Question

Explain the regulatory mechanism related to allosteric enzymes. In your answer address: definition , illustrate and identify key characteristics of the kinetic curve and impact on Km and Vmax. (10)

Answer 1

Allosteric Enzymes consists of several unit cells and subunits. They differ in their quaternary structure. They can switch from being in an active bonding stage to inactive bonding stage. A metabolite modulator upon binding with the enzymes changes the kinetic mechanism of the enzyme. As per the Symmetry model, an allosteric enzyme can exist in still two adaptations, dynamic and loose or idle structure. All subunits are either in the dynamic structure or all are in the inert structure. Each substrate atom that ties with protein builds the likelihood of change from the latent to the dynamic site. The impact of allosteric activators and inhibitors can be clarified effectively by this model. An allosteric inhibitor ties ideally to the T structure through allosteric activator ties to the R structure. An allosteric inhibitor moves The R → T conformational balance towards T. Though an allosteric activator shifts it toward R. The outcome is that an allosteric activator expands the official to the substrate of the protein, though an allosteric inhibitor diminishes substrate authoritative. Symmetry is monitored in this model however not in the successive model.

The Kinetic curve changes significantly as it becomes sigmoidal from being a logarithmic curve. The rate versus concentration of Allosteric Enzyme curve is as follows:-We can see that the Km and Vmax change according to the concentration. Firstly, both factors increase as the concentration increases. Then at a concentration, they keep on increasing but concentration remains constant. Finally, the factors get stabilized and don't change upon changing of concentration. That is called the point of saturation.

AIlosteric enzyme Simple Enzyme Rate Concentration CS Scanned with CamScanner