Enzyme

• what do enzymes do?

  • regulate the flow of molecules through all metabolic pathways
  • build structures of cells (and break them down again)
  • break down invading pathogens and parasites
• what does phosphorylation do to enzymes?

  increase reactivity
• what protects chick embryo from bacteria?

  lysozyme
• what curdels casein in milk?

  chymosin
• what do enzyme do in a reaction?

  • increase rate of reaction
  • remain unchanged after the reaction
  • mostly enzymes
• which proline is more reactive?

  trans
• what enzyme folds up cis and trans enzyme?

  isomerase
• what is an example of a non protein enzyme?

  ribozymes
• what does a high specificity mean for enzymes?

  very specific to a certain degree of substrate
• Low specificity enzyme:

  • subtilisin = bacterial protease that cleaves peptide bonds indiscriminately
• moderate specificity enzyme:

  • trypsin = digestive enzyme that cleaves peptide bonds on the carboxyl sides of lys or Arg
• High specificity enzyme:

  • thrombin = a blood clotting enzyme that cleaves between arg and gly within specific amino acid sequence motif
• who names enzymes?


  International Union of Biochemistry and molecular biology
• What is the enzyme comission?


  Classification system for enzymes, made up of 4 numbers
• what does the first number of enzyme commission mean?


  Major class
• what does the second number of enzyme commission mean?


  bond broken
• what does the forth number of enzyme commission mean?

  gives substrate detail
• what does the thrid number of enzyme commission mean?

  group removed
• how to measure enzyme activity?

  amount of product produced per unit time
• what are the SI unit for enzyme activity?

  katal
• what is a katal?

  The amount of enzyme that converts 1 mol of substrate per second under standard assay conditions
• which is more used katal or international activity unit?

  international activity unit
• what is the international activity?

  An amount of enzyme that will catalyse the transformation of 1 micromole of the substrate per minute under standard assay conditions
• how to calculate equilibriuim constant?


  K of forwards reaction / K of reverse reaction
• what is exergonic?


  reaction releasing energy to surroundings
• what is endogonic?


  other require overall input of energy
• what is the difference between exothermic v exergonic?

  exothermic = heat

  exergonic = release of any type of energy
• what is another term for activation energy?


  Gibbs free energy of activation
• what is free energy?


  Energy in a system that can be converted to perform work. Essentially the amount of energy tired up in the bonds of molecules
• How do enzymes increase reaction rates?

  lowering activation energy
• do enzymes affect the DeltaG?


  No
• who develop the lock and key hypothesis?

  Fischer
• why does the lock and key theory not work?


  Because if it was 100% complementary there would be a lot of interaction between amino acids of the enzymes and amino acids of substrate.

  THIS MAKES IT MORE STABLE, so more energy would be required to break it
• what structure of the enzyme is complementry to the substrate?

  Complementry to transition state
• what enzymes are found in laundry detergents?


  Lipases and proteases for stains

  cellulase for bobbles
• how to get that stonewashed demin look?

  using cellulases
• how are candy fondant centres made?


  invertase breaks down sucrose and prevents it crystallising
• Where is rennet made?

  calf stomach
• what are two enzymes used for cheese making?

  rennet, chymosin
• How do enzymes usually end?


  -ase