Enzymes

Enzymes

1. Structure

   • Protein
   • Tertiary - Quaternary
     • Folded
   • 3D, Globular
   • Specific

2. Factors

   • Temperature
     • Optimum temperature
       • Temperature enzyme works most efficiently at
     • Too cold
       • Slower rate of reaction
         • Less energy
     • Too hot
       • Denaturing
         • Temperature causes H bonds to seperate
           • Chain becomes unfolded
             • Active site changes shape
   • PH
     • Optimum PH
     • Too high PH (alkaline)
       • Slower rate of reaction
     • Too low PH (acidic)
       • H- ions and ionic bonds affected by H+ ions
         • Denaturing
     • Measure of H ion concentration
   • Inhibition
     • Competitive
       • Inhibitor has similar structure to substrate
         • Competes for active site of the enzyme
     • Non competitive
       • Inhibitor binds to site other than active site
         • Causes conformational change

3. Models

   • Induced fit
     • Enzyme + substrate do not perfectly fit
       • But structure is complementary
         • Substrate binds to active site
           • Causes conformational change
             • Enzyme "moulds" around substrate
               • Enzyme catalyses reaction
   • Lock and Key
     • Enzyme + substrate fit perfectly
       • Structure is perfectly complementary
         • Substrate binds to active site
           • Enzyme catalyses reaction

4. Properties

   • Types
     • Builders
       • Joins molecules together
     • Breakers
       • Breaks molecules down
   • Biological catalysts
     • Speeds up reactions
   • Not used up during reaction

5. Examples

   • (Substrate)
     • Starch
       • Maltose
         • Lactose
   • (Product(s))
     • Maltose
       • a glucose
         • Glucose
         • Galactose
   • (Enzyme)
     • Amylase
       • Maltase
         • Lactase