ENZYMES AND THEIR APPLICATIONS

ENZYMES AND THEIR APPLICATIONS

1. WHAT ARE ENZYMES?

   • A catalyst is a substance that speeds up a chemical reaction without being consumed in the process.
     • Catalysts lower the activation energy
     • THREE KEY ASPECTS OF CATALYST'S ACTION
       • Catalyst can alter the rate of a chemical reaction
       • After the reaction cycles, a catalyst with the exactly the same nature is "reborn".
       • Catalyst will change itself during the process by interacting with other reactants/products.
     • An example of a biological catalyst is the enzyme maltase. It catalyzes the hydrolysis of maltose into two separate glucose molecules.
   • An enzyme is a protein catalyst which composed of amino acids chains that are in the tertiary or quaternary form with complex conformations.
     • Enzyme are made up of amino acids which are linked together via peptide bond in a linear chain (Primary Structure).
       • The primary structure of an enzyme is so important because this structure determines the overall conformation of the protein in which the enzyme is made of during the protein synthesis.
         • Changes in pH or temperature will result in the changes of the protein's final conformation.
         • Changes in the protein's primary structure can result is denaturation, leaving it unable to perform its specific functions.
       • Enzymes rely on having a very specific three-dimensional structure to work right. If the temperature around an enzyme gets too high, the enzyme loses its shape, which is known as denaturation, leaving it unable to perform its specific functions.
       • Tertiary structure of an enzyme is important because the function of an enzyme depends on its tertiary structure. If the structure is disrupted, the enzyme will lose its catalytic power.
     • After the catalytic reaction, the enzyme releases its substrate and further catalyzes
     • Enzyme’s names usually ends with the term “ase”. For example: maltase, amylase, and lipase. However, they sometimes end with the term "sin". For example: trypsin and pepsin.

2. HOW DO ENZYMES WORK?

   • DISTINGUISH BETWEEN ENZYME QUATERNARY STRUCTURE AND ACTIVE SITE
     • Quaternary structure occurs when two or more polypeptide subunits formed a functional protein.
     • Active site is the location where the substrate binds to an enzyme.
       • An enzyme's active site lower the activation energy by stretching and bending chemical bonds that would usually break in a reaction
   • DISTINGUISH BETWEENSUBSTRATE AND ENZYME-SUBSTRATE COMPLEX
     • Substrate is the reactant that an enzyme acts on when it catalyzes a chemical reaction.
     • Enzyme-substrate complex is an enzyme with its substrate attached to the active site.
   • The substrate model of enzyme activity is called the "induced fit model of enzyme-substrate interaction" because it refers to the interaction between the functional groups of the substrate and the functional groups of the amino acids in the protein, causing the enzyme to change its shape in order to acommodate its substrate
     • Since that enzymes aren't consumed during the reaction, the shape of an enzyme after the reaction is the exactly the same shape before the reaction occurs.

3. Which environmental factors affect enzyme activity?

   • Optimum Temperature. Each enzyme has a temperature that works optimally in, which in humans is around 98.6 degrees Fahrenheit , 37 °C – the normal body temperature for humans.
   • OPTIMAL LEVEL PH LEVELS FOR PEPSIN AND TRYPSIN
   • Since it takes some time for a catalyst to catalyze a particular reaction, the speed at which a catalyzed reaction proceeds cannot increase indefinitely by increasing the concentration of the substrate because there are limited number of a specific enzyme molecules in a cell at any one time.

4. WHY DO CELLS REQUIRE ENZYMES?

   • Enzymes lower the activation energy of a chemical reaction. The lower the activation energy, the faster the rate of the reaction.
   • Enzymes are biological catalyst in metabolic reactions (digestion) as they allow substrates to bind onto their active site, breaking them down into products.
   • . Living cells cannot rely on high levels of heat as a source of activation energy when one of its enzymes became non functional.

5. WHAT OTHER MOLECULES AFFECT ENZYME ACTIVITY?

   • DISTINGUISH BETWEEN CO-FACTOR AND CO-ENZYME AND GIVE EXAMPLE OF EACH
     • Co-factors are the non-protein components, such as dissolved ions, that are needed to some enzymes to function.
       • An example of a co-factor is zinc ions (Zn2+)
     • Co-enzymes are the organic non-protein co-factors that are needed for some enzymes to function.
       • An example of co-enzyme is nicotinamide adenine dinucleotide (NAD+)
   • Allosteric site is the place on an enzyme that are some distance away from the active site where a molecule that is not a substrate may bind, thus changing the shape of the enzyme and influencing its ability to be active.
     • How do allosteric activators and allosteric inhibitor wrks?
       • Inhibitors cause the allosteric enzyme to adopt the inactive shape.
       • Activators promote the active shape.
       • Not all allosteric inhibitors are competitive. Some are noncompetitive, which attach to the allosteric sites of certain enzymes.
   • How do inhibitors affect enzyme activity?
     • Competitive inhibitors are those inhibitors that mimics the shape of the actual substrate and binds to the active site.
       • Activity decrease in presence of competitive inhibitor
     • Non-competitive inhibitors do not compete for the active site with substrate but does not allow substrate to bind at the active site.
       • Non-Competitive Inhibitors do not allow the substrate to bind at the active site.
     • Not all enzyme inhibitors are dangerous to the cell. Some are used by the cell to control cell activity.

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