2.1.4 Enzymes

• Metabolism is the sum of all chemical processes that occur within a living organism in order to maintain life
• Anabolic Reactions are Building up
• Catabolic Reaction are Breaking Down
• Intracellular means that they function inside cells.
• Extracellular means that they function outside of cells.
• Enzymes are globular proteins. The shape of the active site is determined due to the tertiary structure of the protein.
• What is the role of Catalase in the body?

  It breaks down the Hydrogen Peroxide (which is a toxic product of metabolic pathways that build sup inside cells) into water and oxygen quick enough to prevent its accumulation in the cells . It would damage and cause cell death
• What is the Equation of Hydrogen Peroxide?

  A) Water

  B) Oxygen

  C) Hydrogen Peroxide

  
• Why are Extracellular Enzymes important?

  • All of the reactions in cells need substrates to make products. These raw materials are constantly supplied in the diet to cells to keep up with demand.
  • Nutrients are often in the form of polymers → too big to enter cells directly → need to be broken down into molecules small enough to enter a cell.
• Amylase is produced in which 2 places?

  Salivary Gland for digestion in the mouth and

  Pancreas for digestion in the small intestine
• Maltase is produced in the?


  pacreas
• If Trypsin breaks down protein it is a?


  Protease Enzyme
• Trypsin first breaks proteins down into smaller polypeptide chains which other enzymes then break them further down into Amino Acids
• How do single called organisms absorb large molecules ?

  • Single called organisms (like bacteria or yeast) secrete enzymes into their immediate environment
  • They break down large molecules such as proteins and the smaller molecules produced such as Amino Acids, can be absorbed by the cells
• Activation energy is the energy required for a chemical reaction to start
• Activation energy is needed to break the bonds in the reactants
• By reducing the activation energy required with enzymes - the chances of a successful collision increases - speeding up the rate of reaction
• This is the Lock and Key Theory of Enzyme Action.

  
• This is the Induced Fit theory of enzyme action. The active site is complementary to the substrate and the enzyme is held in place by the bonds between the substrate and the active site.

  
• What does ‘Optimum’ mean?

  It is the point at which a reaction has the highest rate of reaction
• The optimum temperature is not the same in all organisms
• What is the optimum temperature for enzymes in the human body?

  Around 37 degrees
• What are Cofactors?

  Inorganic “helper” components that are obtained in the diet from mineral ions
• What is a Prosthetic Group?

  A Type of cofactor that is a permanent,necessary non-protein feature of an enzyme - tightly bound
• Coprosthetic groups are:

  • Not changed or used up in a reaction
  • Able to bind/interact with substrate to help it bind with active site
  • Able to help the enzyme and substrate bind together
• The Coprosthetic Group can:

  • Form part of the active site or change the shape of the active site
  • Transfer atoms or groups from one reaction to another in a multi step pathway
• Cofactors can leave and will detach themselves
• Prosthetic groups are permanent
• The cofactor is a molecule that is required for the enzyme to work
• The Cofactor Amylase pairs with a Chloride Ion .
• A Chloride ion is necessary for the formation of the correctly shaped active site without it the enzyme and active site is the wrong shape
• The Cofactor Carbonic Anhydrase Active Site always contain Zinc , in order to be the right shape to break down carbon dioxide
• The Zinc ions are a permanent part of the Active Site
• Prosthetic Groups are cofactors but they are tightly bound and are permanently attached to the enzyme
• What are Coenzymes?

  Oranic “Helper” Components
• Coenzymes can:

  • Bind loosely to the enzyme for a short period of time
  • Participate in the reaction an are change by it
  • Often act as carriers, moving chemical groups between different enzymes
• Co Enzymes can:

  • Be continually recycled during this process to be used again
  • Can also bind to/interact with substrate to help it bind with the active site
• Vitamin B3 is needed to make the coenzyme NAD
• Vitamin B5 is used to make Coenzyme A
• The Vitamin B3 that is used to make the coenzyme A is used to transfer H atoms between molecules involved in respiration