Enzymes

Enzymes are…

• Catalysts– is any substance that works to accelerate a

chemical reaction• Most enzymes are proteins

How do catalysts speed up reactions?

• The activation energy in chemistry is the energy needed by a system to initiate a particular process

• Catalysts decrease activation energy

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Lock and Key model

Active Site

• Substrate: substance that an enzyme reacts with

• Active Site: part of the enzyme that reacts or binds to the substrate

Enzyme-Substrate Complex

Enzymes are specific and Complementary

• Complementary: complement one another; shaped for precise pairing

• Specific: particular, precise– Only the correct substrate can fit into the

enzyme’s active site

Enzymes end in -ase

• Carbohydrase- breaks down carbohydrates into simple sugars

• Amylase- breaks down starch• Protease – breaks down proteins into amino

acids• Lipase- breaks down lipids into fatty acids and

glycerol

Digestive End productsMacromolecule Digestive End Product

Carbohydrate Simple Sugar

Protein Amino Acids

Lipid 3 fatty acids and glycerol

Nucleic Acid Nucleotide

Temperature effects enzymes• Increasing

temperature increases enzyme activity until it reaches an optimum value

• Increasing temperature past that point denatures the enzyme

Denature

• shape of the protein is altered through some form of external stress

• will no longer be able to carry out its cellular function

pH effects enzymes

• Certain pH value causes optimal enzyme activity

• Too low or too high pH will denature the enzyme

Enzymes are reused or recycled

• In a written equation, enzymes appear on both the reactant and product side

• Substrate + enzyme enzyme and products reactants products• They are not used up• They are recycled and being used over and

over gain

• The function of most proteins depends primarily on the

(1) type and order of amino acids(2) environment of the organism(3) availability of starch molecules(4) nutritional habits of the organism

• Enzyme molecules normally interact with substrate molecules. Some medicines work byblocking enzyme activity in pathogens. Thesemedicines are effective because they

(1) are the same size as the enzyme(2) are the same size as the substrate molecules(3) have a shape that fits into the enzyme(4) have a shape that fits into all cell receptors

• The diagram below represents two molecules that can interact with each other to cause a biochemical process to occur in a cell.

Molecules A and B most likely represent(1) a protein and a chromosome(2) a receptor and a substrate(3) a carbohydrate and an amino acid(4) an antibody and a hormone