Background – Enzymes Enzymes are compounds that facilitate chemical reactions. These compounds are proteins found in living organisms and are very important for cells to live and function. Most enzymes end in --ase
For example, the food that you eat is broken down into smaller pieces by different enzymes known as the digestive enzymes. Some examples are proteases, lipases and carbohydrases. • What do you think these are used for?
Protease- enzyme that breaks down other protein molecules • Lipase- enzyme that breaks down other lipid molecules • Carbohydrases- enzyme that breaks down other carbohydrate molecules
What are they? Enzymes are catalysts. Catalysts are compounds that accelerate a reaction without being changed. Enzymes are not destroyed or changed, but rather reused in the same chemical reaction over and over.
The compounds that enzymes act upon are known as substrates. Enzymes bind to an active site in the substrate and lower the energy needed for the reaction to occur making it faster. Video #1- http://www.youtube.com/watch?v=V4OPO6JQLOE Video #2-http://www.youtube.com/watch?v=TLr7_2wnIXU&feature=related Video #3- http://www.youtube.com/watch?NR=1&v=Pvgpk75us18
The energy required for a chemical reaction to occur is known as the activation energy. The explanation of what happens lies in the fact that most chemical reactions that RELEASE ENERGY (exothermic reactions) require an INPUT of some energy to get them going. The initial input of energy is called the ACTIVATION ENERGY. Catalysts act by BINDING the molecules they act on in a way that makes it much easier for them to do what THEY WANT TO DO ANYWAY at the energy level (the temperature) currently in the environment. In our bodies this temperature is 37oC or 98.6oF.
Analogy I • An analogy is that of a couple that like each other, but are too shy to make the first move. But a friend (I. M. A. Catalyst) invites them to dinner & seats them beside each other. Later he arranges that one of them will have to take the other home. No one is surprised when the couple subsequently become "an item"; we even describe them as "having the right CHEMISTRY". The couple involved didn't have the ENERGY of ACTIVATION to get together on their own, but I. M. A. Catalyst LOWERED the amount of energy by putting the couple in a situation where nature could TAKE ITS COURSE.
Analogy II • Another analogy is the use of a starter (small amount of input energy) to start a car which will then run on its own all day.An enzyme works in much the same way; i.e. by binding the components of a potential reaction together in a situation where the activation energy is much lower: i.e., LOWERING the activation energy, enzymes start the reaction going, after which it runs on its own