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Enzymes

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Proteins found in ALL Living cells.

Enzymes are biological catalysts that speed up reactions

but are not used up.





 

Enzyme reactions


Enzymes bind to a specific molecule called a substrate which is changed into a
 
second molecule called the product by the substrate binding to its enzymes 

active site.


 

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Enzyme Equations

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Specificity of Enzymes

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The shape of the active site is complementary to a specific substrate.


 

   Active site

complementary


 

    Active site
not complementary


 

     Specific
    substrate


 

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    Non Specific
      substrate


 

Types of Reactions

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When a smaller substrate is converted into a larger product by an enzyme
that is unchanged in the reaction.  e.g. phosphorylase


 

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Types of Reactions

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When a larger substrate is broken down into a smaller product by an enzyme
that is unchanged in the reaction.


 

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Factors affecting Enzyme Activity

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Two factors affecting enzyme activity.

1.                                 2.          


 

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The temperature/pH that enables highest enzyme activity.
                                 

1. Temperature

2. pH

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Different enzymes have different optimum pH 


 

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The active site changes shape 
 
1.  At high temperature      2.  Outside working pH range for that enzyme

Reaction rate decrease/stops.


 

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Working range
Pepsin   1 -8   Optimum = 4
Amylase 4-12   Optimum = 8
Catalase 8-14  Optimum = 12


 

Specificity of Enzymes

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