Enzymes are protein molecules that act as biological catalysts through their ability to increase the rate of the reaction without being used up. Enzymes are fundamental to cellular metabolism because without them reactions in the body would be too slow to enable functioning.
Enzymes work by binding a substrate into a cavity known as an active site forming an enzyme-substrate complex and then releasing the product, the enzyme is then free to catalyse further reactions. The binding of the enzyme and the substrate works like a lock and key mechanism and hence is called the lock and key model. The reality is however, the enzymes do not always have a perfect it so we often refer to it being a induced fit model.
Activation energy is the minimum energy required for a reaction to occur, through a substrate binding to enzyme there is a reduction in the activation energy so the energy barrier that is required for the reaction to proceed is lower, so it can occur more easily. Enzymes do not change the amount of product produced they only have affects on the rate of a reaction.
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A molecule competes with the substrate for binding to the enzyme’s active site, preventing the binding of enzyme and substrate.
A molecule that binds to an enzyme at another part other than the active site which causes a conformational change to the enzyme’s active site so the substrate can no longer bind.
In recent times drugs have been synthesised to block active sites of particular enzymes in order to combat some decisions. For example, Relenza blocks the action of an enzyme known as neuraminidase, which is needed to release viruses from infected cells.
Some enzymes require another chemical component to attach to the protein in order to work. If organic we refer to them as coenzymes, if inorganic we refer to them as cofactors.
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