how enzyme works and get inhibited
...l product 3. Stereospecificity between the enzyme and its substrate, and the electrical charges located on the enzyme and the substrate must be ˇ°compatibleˇ± are the two essential conditions in order to an enzymatic reaction to proceed. 4. Certain changes of condition, such as changes in temperature, pH, and concentrations of substrate and enzyme, affect the rate of reaction. Increased temperature would increases the speed of molecular movement and causes the chances of molecular collisions, and also the enzyme will be denaturated, the shape of active site will be changed and therefore the enzyme is inactivated permanently. And when the temperature gets to low, the whole reaction will be inhibited. So only within a range of 0-45oC, enzyme could work properly. Changes in the pH can cause different efficiency of reaction process; a proper pH for enzyme and substrate could react is near to 7. Any slow down or stop of a enzyme catalyzed reaction is called the reaction is inhibited. There are generally two types of inhibition that can affect enzyme catalyzed reactions: competitive and non-competitive inhibition. 1. Competitive inhibition By the name, we know this type of inhibition is about a competition. Because the inhibitor molecules compete with the substrate molecules, it binds with active site ahead of substrate and blocks the enzyme. Example: One of the enzymes needed for the respiration catalyses the oxidation (by the removal of two hydrogen atoms) of succinate acid ((a) in the diagram) to fumarate. Succinate fumarate If malonate ((b) in the diagram) is added to a mixture of succinate and the enzyme, the action of the enzyme is strongly inhibited. This is because the structure of malonate allows it to fit into the active site of the enzyme. As there is no reaction when this occurs products are not quickly released and the site is temporarily blocked. The inhibition is ...