Enzyme inhibitors | Competitive and non-competitive inhibitors | Feedback inhibition скачать в хорошем качестве

Enzyme inhibitors | Competitive and non-competitive inhibitors | Feedback inhibition

Certain chemicals selectively inhibit the action of specific enzymes. Sometimes, the inhibitor attaches to the enzyme by covalent bonds, in which case the inhibition is usually irreversible. Many enzyme inhibitors, however, bind to the enzyme by weak interactions, and when this occurs the inhibition is reversible. Some reversible inhibitors resemble the normal substrate molecule and compete for admission into the active site. These mimics, called competitive inhibitors, reduce the productivity of enzymes by blocking substrates from entering active sites. This kind of inhibition can be overcome by increasing the concentration of substrate so that as active sites become available, more substrate molecules than inhibitor molecules are around to gain entry to the sites. In contrast, noncompetitive inhibitors do not directly compete with the substrate to bind to the enzyme at the active site. Instead, they impede enzymatic reactions by binding to another part of the enzyme. This interaction causes the enzyme molecule to change its shape in such a way that the active site becomes less effective at catalyzing the conversion of substrate to product. Toxins and poisons are often irreversible enzyme inhibitors. Many antibiotics are inhibitors of specific enzymes in bacteria. For instance, penicillin blocks the active site of an enzyme that many bacteria use to make their cell walls. feedback inhibition, a metabolic pathway is halted by the inhibitory binding of its end product to an enzyme that acts early in the pathway. For more information watch complete video. Thank you