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Enzyme Kinetics

Enzyme KineticsAhmed Nawaz13ch153Waleed Shaikh13CH03Talal Ashraf13CH10Muzamill Hussain13CH19Inayat Morio13CH136

Contents:EnzymeEnzyme KineticsParametric Analysis of enzyme catalysisEnzyme specific to substrateKey And Lock ModelMichaelis Menten Kinetics Model for Enzyme

EnzymesEnzymes are usually protein molecules that manipulate other molecules the enzymes' substrates. These target molecules bind to an enzyme's active site and are transformed into products through a series of steps known as the enzymatic mechanism. These mechanisms can be divided into single-substrate and multiple-substrate mechanisms.

IntroductionEnzyme KineticsEnzyme kinetics is the study of the chemical reactions that are catalyzed by enzymes. In enzyme kinetics, the reaction rate is measured and the effects of varying the conditions of the reaction is investigated. Studying an enzyme's kinetics in this way can reveal the catalytic mechanism of this enzyme, its role in metabolism, how it activity is controlled, and how a drug or an agonist might inhibit the enzyme.

Parametric Analysis of Enzyme CatalysisIt is often asserted that enzymes are more active, i.e., allow reactions to go faster, than non biological catalysts.At the ambient temperatures where enzymes are most active they are able to catalyze reactions faster than the majority of artificial catalysts. When the reaction temperature is increased, solid (synthetic) catalysts may become as active as enzymes. The enzyme activity does not increase continuously as the temperature is raised. Instead, the enzyme usually loses activity at quite a low temperature, often only slightly above that at which it is typically found.

How are enzymes specific to substrates?Enzymes are specific to substrates as they have an active site which only allow certain substrates to bind to the active site. This is due to the shape of the active site and any other substrates cannot bind to the active site.There is a model which is well known in the biology field of the lock and key model. This is because you have to have the correct key to insert it into the lock. This goes the same as an enzymes active site and the substrate.

Key And Lock Model

MichaelisMenten kinetics

As enzyme-catalyzed reactions are saturable, their rate of catalysis does not show a linear response to increasing substrate. If the initial rate of the reaction is measured over a range of substrate concentrations (denoted as [S]), the reaction rate (v) increases as [S] increases, as shown on the right. However, as [S] gets higher, the enzyme becomes saturated with substrate and the rate reachesVmax, the enzyme's maximum rate.

Mathematical Model For Enzyme Kinetics

This equation is calledMichaelisMenten equation.

Where,

Here, Vmaxrepresents the maximum rate achieved by the system, at maximum (saturating) substrate concentrations.

The Michaelis constant Kmis the substrate concentration at which the reaction rate is half of Vmax.