D
,ENZYMES
Enzymes are organic catalysts that speed up chemical reactions inside living cells. They are usually proteins
in nature. They are not used up in the chemical reaction itself and they always end in -ase.
These chemical reactions are known as metabolic reactions and
Catalysts have 2 functions: Y they can either be:
- speed up chemical reactions - Anabolic ( built up + energy required )
- control and regulate all chemical reactions - In a reaction, if there is more reactants and 1 product = A
So that they occur at the best or possible - Catabolic ( broken down + energy released - eg. Hydrolysis )
optimum rate - In a reaction, if there is 1 reactant and more products = C
~
Optimum Rate —> the rate at which the most product is formed in the shortest space of time
Carbohydrate Enzymes
Disaccharides Polysaccharides
Maltase Amylase
Maltose + Water &
Glucose + Glucose Starch + Water Maltose
Sucrase
Sucrose + Water Y Glucose + Fructose
Lactase
Lactose + Water & Glucose + Galactose
Lipids Proteins
Lipase Protease
Lipids + Water & Glycerol + 3 fatty acids Proteins + Water >
Smaller polypeptides
Lock and Key Theory
Enzymes needs the help of a partner and they are known as co-enzymes. These are organic and non-protein in
nature. They loosely bound to the enzyme
⑦ M
E Substrate ( lock ) - substance
in which enzyme works
Enzyme ( key ) - has specific
shape
V
Active Site - part of the enzyme Enzyme Substrate Complex
where substrate attaches
Enzymes function by lowering the activation energy in order to start the chemical reaction. Activation energy is
the minimum amount of energy required to start a reaction.
, S
Activation Energy ↓
Reactants Products Reactants Products
No Enzyme With Enzyme
Temperature Effects on Enzymes
- Enzymes are sensitive to temperature changes Denaturation - irreversible process where the
- Low temperatures temporarily inactivate enzymes shape of the enzyme changes ( shape
- Optimum temperature is the temperature at which most determines function - globular shape ) This
enzymes work the best stops/slow downs the reaction due to the
- If the temperature is too high, it can denature substrate not being able to fit in the enzyme
the enzyme
Acidic Alkaline PH Effects on Enzymes
- Optimum pH is a pH-range in which enzymes peak
1 - Enzymes can be denatured at extreme pH levels
7 14
for they are very specific
Low pH High pH
Neutral
Enzyme Properties Enzyme Uses
- Enzymes are spherical proteins - meat tenderizer
- They are sensitive to temperature changes ( high - removes hair from skin
temperature = denatured and low temperatures = - used in beet, vinegar, wine
temporarily inactive ) - used in chocolate and syrup
- Sensitive to pH changes ( denatured if changed - used in washing powders
drastically ) - more expensive washing powders = more then 1 enzyme
- Substrate specific - most contains protease which breaks down protein
- Used over and over ( not used up in reaction ) ( removes blood, egg and gravy )
- Small amounts of enzymes can change large amounts - other contain amylase ( removes grease stains )
of substrate - lipase breaks down lipids
,ENZYMES
Enzymes are organic catalysts that speed up chemical reactions inside living cells. They are usually proteins
in nature. They are not used up in the chemical reaction itself and they always end in -ase.
These chemical reactions are known as metabolic reactions and
Catalysts have 2 functions: Y they can either be:
- speed up chemical reactions - Anabolic ( built up + energy required )
- control and regulate all chemical reactions - In a reaction, if there is more reactants and 1 product = A
So that they occur at the best or possible - Catabolic ( broken down + energy released - eg. Hydrolysis )
optimum rate - In a reaction, if there is 1 reactant and more products = C
~
Optimum Rate —> the rate at which the most product is formed in the shortest space of time
Carbohydrate Enzymes
Disaccharides Polysaccharides
Maltase Amylase
Maltose + Water &
Glucose + Glucose Starch + Water Maltose
Sucrase
Sucrose + Water Y Glucose + Fructose
Lactase
Lactose + Water & Glucose + Galactose
Lipids Proteins
Lipase Protease
Lipids + Water & Glycerol + 3 fatty acids Proteins + Water >
Smaller polypeptides
Lock and Key Theory
Enzymes needs the help of a partner and they are known as co-enzymes. These are organic and non-protein in
nature. They loosely bound to the enzyme
⑦ M
E Substrate ( lock ) - substance
in which enzyme works
Enzyme ( key ) - has specific
shape
V
Active Site - part of the enzyme Enzyme Substrate Complex
where substrate attaches
Enzymes function by lowering the activation energy in order to start the chemical reaction. Activation energy is
the minimum amount of energy required to start a reaction.
, S
Activation Energy ↓
Reactants Products Reactants Products
No Enzyme With Enzyme
Temperature Effects on Enzymes
- Enzymes are sensitive to temperature changes Denaturation - irreversible process where the
- Low temperatures temporarily inactivate enzymes shape of the enzyme changes ( shape
- Optimum temperature is the temperature at which most determines function - globular shape ) This
enzymes work the best stops/slow downs the reaction due to the
- If the temperature is too high, it can denature substrate not being able to fit in the enzyme
the enzyme
Acidic Alkaline PH Effects on Enzymes
- Optimum pH is a pH-range in which enzymes peak
1 - Enzymes can be denatured at extreme pH levels
7 14
for they are very specific
Low pH High pH
Neutral
Enzyme Properties Enzyme Uses
- Enzymes are spherical proteins - meat tenderizer
- They are sensitive to temperature changes ( high - removes hair from skin
temperature = denatured and low temperatures = - used in beet, vinegar, wine
temporarily inactive ) - used in chocolate and syrup
- Sensitive to pH changes ( denatured if changed - used in washing powders
drastically ) - more expensive washing powders = more then 1 enzyme
- Substrate specific - most contains protease which breaks down protein
- Used over and over ( not used up in reaction ) ( removes blood, egg and gravy )
- Small amounts of enzymes can change large amounts - other contain amylase ( removes grease stains )
of substrate - lipase breaks down lipids
