• Enzymes are proteins that act as catalysts and help complex reactions occur everywhere in life.
• Catalyst- a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change
• Examples: enzymes in saliva & intestines to help breakdown food

• A substrate is a molecule upon which an enzyme acts.
• The substrate bonds with the enzyme active site, and an enzyme-
substrate complex is formed.

• Enzymes control the speed of chemical reactions in your body.
• Without enzymes, reactions would be too slow to keep you alive.
• Catabolic enzymes: enzymes break down large molecules into smaller ones.
– Ex: pepsin in stomach
• Anabolic enzymes: use small molecules to build up large complex ones.
– Ex: enzymes that make DNA
• Enzymes also help cells to communicate with each other, keeping cell growth, life and death under control.

• lactase – breaks down lactose (milk sugars)
• Enzymes are commonly
named by adding a suffix "ase" to the root name of the substrate molecule it is acting upon.
• For example, Lipase catalyzes the hydrolysis of a lipid triglyceride.
• Sucrase catalyzes the hydrolysis of sucrose into glucose and fructose.
• diastase – digests vegetable starch
• sucrase – digests complex sugars and starches
• maltase – digests disaccharides to monosaccharides (malt sugars)
• glucoamylase – breaks down starch to glucose
• protease – breaks down proteins found in meats, nuts, eggs, and cheese
• lipase – breaks down fats found in most dairy products, nuts, oils, and meat
• cellulase – breaks down cellulose, plant fibre; not found in humans

• Enzymes are made from amino
acids, and they are proteins.
• When an enzyme is formed in a ribosome, it is made by stringing together between 100 and 1,000 amino acids in a very specific and unique order.
• The chain of amino acids then folds into a unique shape.
• That shape allows the enzyme to carry out specific chemical reactions -- an enzyme acts as a very efficient catalyst for a specific chemical reaction.
• The enzyme speeds that reaction up tremendously.

• In this analogy, the lock is the enzyme and the key is the substrate.
• Only the correctly sized key (substrate)
fits into the key hole
(active site) of the
lock (enzyme).

• When an enzyme binds to the appropriate substrate, subtle changes in the active site occur.
• This alteration of the active site is known as an induced fit .
• Induced fit enhances catalysis, as the enzyme converts substrate to product.
• Release of the products restores the enzyme to its original form.
• The enzyme can repeat this reaction over and over, as long as substrate molecules are present.

• In biology, the active site is a small port in an enzyme where substrate molecules bind and undergo a chemical reaction.
• This chemical reaction occurs when a substrate collides with and slots into the active site of an enzyme.

• Coenzymes are small molecules.
• They cannot by themselves catalyze a reaction but they can help enzymes to do so.
• In technical terms, coenzymes are organic nonprotein molecules that bind with the protein molecule to form the active enzyme.

• Thiamine Pyrophosphate
– found in Vitamin B, meat, leafy green vegetables
– Function: used when glucose is converted to ATP
• Flavin adenine dinucleotide
(FAD)
– found in vitamin B, milk, meat
– Function: reactions in mitochondria (Energy)
• Nicotinamide adenine dinucleotide (NAD)
– found in vitamin Niacin, meat, leafy green vegetables
– Function: carries hydrogen during energy production