ENZYMES

ENZYMES

1. ENZYMES AND WHAT THEY DO

   • ENZYMES ARE MADE UP FROM PROTEINS AND SO ARE MADE OF LONG CHAINS OF AMINO ACIDS FOLDED IN DIFFERENT SHAPES
   • THEY ARE BIOLOGICAL CATALYSTS THAT SPEED UP REACTIONS WITHOUT BEING USED UP
   • THEY ARE INVOLVED IN MULTIPLE REACTION EG. PROTEINSYNTHESIS, RESPIRATION AND DIGESTION
   • THEY CAN EITHER
     • BUILD LARGE MOLECULES
       • FROM SMALL ONES
         • EG, PROTEINSYNTHESIS
     • BREAK DOWN LARGE MOLECULES
       • INTO SMALLER ONES
         • EG, DIGESTION
   • YOU CAN USUALLY MAKE A REACTION HAPPEN FASTER BY RAISING THE TEMPERATURE HOWEVER THERE IS A CERTAIN LIMIT TO WHICH YOU CAN RAISE THE TEMPERATURE TO BEFORE THE CELLS START TO DE-NATURE
     • SO LIVING THINGS PRODUCE ENZYMES WHICH SPEED UP REACTIONS WITHOUT THE EFFECT TEMPERATURE WOULD AND WHILE THEY SPEED UP THE REACTION NOTHING HAPPENS TO THE MOLECULE ITSELF
       • BIOLOGICAL CATALYSTS
       • EVERY DIFFERENT BIOLOGICAL REACTION HAS ITS OWN ENZYME
       • EACH ENZYME IS A PROTEIN CODED FOR BY A DIFFERENT GENE AND HAS A UNIQUE SHAPE WHICH IS NEEDED FOR IT TO DO ITS JOB
   • CHEMICAL REACTIONS USUALLY INVOLVE THINGS EITHER BEING BROKEN DOWN OR PUT TOGETHER
   • EVERY ENZYME HAS AN ACTIVE SITE THE PART WHERE IT JOINS ONTO THE SUBSTRATE TO CATALYSE THE REACTION
   • ENZYMES ARE REALLY PICKY- THEY ONLY WORK WITH ONE SUBSTRATE THE POSH WAY OF SAYING THIS TO SAY THEY HAVE A HIGH SPECIFICITY FOR THEIR SUBSTRATE

2. SUBSRATES AND ACTIVE SITE

   • THE SHAPE OF THE ENZYME ACTIVE SITE IS IMPORTANT AS IT IS WHERE THE SUBSTRATE FITS
   • ENZYMES ARE HIGHLY SPECIFIC, THEY ONLY BOND TO ONE TYPE OF SUBSTRATE MOLECULE AND IF THE SUBSTRATE DOES NOT FIT THEN THE REACTION CANNOT HAPPEN
   • LOCK AND KEY HYPOTHESIS
     • THE IDEA IS THAT THE SUBSTRATE AND THE ENZYME WORKS AS A LOCK AND KEY. THE ENZYME BEING A LOCK AND THE SUBSTRATE A KEY
     • THE SUBSTRATE IS THE MOLECULE BEING MADE OR BROKEN DOWN
     • THIS IS BECAUSE IN ORDER FOR THE ENZYME TO WORK THE SUBSTRATE HAS TO FIT INTO THE ACTIVE SITE IF THE SUBSTRATE DOESN'T MATCH THEN THE REACTION WILL NOT BE CATALYSED THIS IS CALLED THE LOCK AND KEY HYPOTHESIS

3. FACTORS THAT EFFECT ENZYMES

   • TEMPERATURE
     • THIS IS BECAUSE IF THE TEMPERATURE IS TOO LOW THEN THE ENZYME WILL NOT WORK HOWEVER IF THE TEMPERATURE IS TOO HIGH THEN THE ENZYME WILL DE NATURE AND THE PROTEIN WILL NOT WORK SO THE TEMPERATURE HAS TO BE CERTAIN FOR THE ENZYME TO WORK AT ITS OPTIMUM
     • THE AMOUNT OF ENZYME
       • TO INCREASE THE RATE OF REACTION YOU CAN INCREASE THE AMOUNT OF ENZYME HOWEVER THE SUBSTRATES MUST BE PRESENT IN AN EXCESS AMOUNT
       • THE AMOUNT OF SUBSTRATE
         • PH
           • ENZYMES ARE EFFECTED BY CHANGES IN PH , ENZYMES WORK BEST AT THE OPTIMUM PH SHOWN IN THE GRAPH IF THE PH IS HIGHER OR LOWER THE ENZYME WILL NOT WORK, THE OPTIMUM PH VALUE FOR EACH ENZYME WILL VARY FROM ONE ENZYME TO ANOTHER
         • INCREASING THE AMOUNT OF SUBSTRATE CAN INCREASE THE SPEED OR THE VELOCITY OF THE REACTION UNTIL IT REACHES A MAXIMUM, AFTER THIS POINT WHEN MAXIMUM VELOCITY HAS BEEN INCREASED AND ALL AVAILABLE ENZYMES HAVE BEEN CONVERTED INTO ES (ENZYME SUBSTRATE COMPLEX ADDING MORE SUBSTRATE WILL NOT INCREASE THE RATE OR REACTION AS THERE ARE NO ENZYMES AVAILABLE TO CAYALYSE THE REACTION

4. ENZYME REACTIONS

   • FOR A REACTION TO HAPPEN YOU NEED TO HAVE ENOUGH ENERGY (KE) FOR THE PARTICLES TO COLLIDE , THE MORE COLLISIONS HAPPENING FREQUENTLY THERE IS MORE CHANCE OF A SUCCESSFUL REACTION
   • TEMPERATURE GRAPH
     • ENZYME HAS DE-NATURED AND HAS STOPPED WORKING. THE PROTEIN STARTS TO UNRAVEL, THIS CHANGES THE STATE OF THE ACTIVE SITE AND THE SUBSTRATE CAN NO LONGER FIT SO NO REACTION
     • REACTION IS AT ITS FASTEST
       • OPTIMUM REACTION RATE
     • THERE IS NOT ENOUGH ENERGY FOR THE REACTION TO HAPPEN
   • SUBSTRATE CONCENTRATION
     • THE ENZYMES BECOME A LIMITING FACTOR SLOWING DOWN THE REACTION
   • ENZYME CONCENTRATION
     • SUBSTRATE BECOMES A LIMITING FACTOR
     • INACTIVE
   • PH
     • PH IS TOO HIGH IT HAS DE-NATURED

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