What Are Enzymes? An enzyme is a catalyst in cellular reactions. DEFINE catalyst Enzymes are protein or nucleic acids with (tertiary and quaternary structure).

Enzymes have specificity Are reusable End in -ase -Sucrase -Lactase -Maltase

Parts of a chemical reaction: Chemical reactions control all of the chemical compounds in our body allowing us to move, grow, react, and even reproduce. Parts of a chemical reaction: The sum of all of the chemical reactions that occur in our bodies is called metabolism. Reactants ------------> Products

Catabolism Chemical reactions in which molecules are broken done and release energy; degradation Example: Hydrolysis

Anabolism Chemical reactions in which molecules are assembled, usually they require energy; synthesis Example: Dehydration Synthesis

catabolism + anabolism = metabolism the sum of all chemical reactions with a living organism catabolism + anabolism = metabolism

What is lactose intolerance then? Why do we need enzymes? ENZYMES! Reactants ------------> Products Enzymes catalyze the chemical reactions in our body What is lactose intolerance then?

How do enzymes work? The Enzyme-Substrate Complex Each enzyme has a unique 3-D shape, including a surface groove called an active site. The enzyme works by binding a specific chemical reactant (substrate) to its active site, causing the substrate to become unstable and react. The resulting product is then released from the active site.

How Do Enzymes Work? Enzymes work by weakening bonds which lowers activation energy.

Active Site Active Site Enzyme Substrate

Shape of a Protein ...Structure Meets Function An enzyme fits with its substrate like a ____ and ____. Enzyme have specificity.

4 levels of Protein Structure

How important is the shape of an enzyme? Which substrate would be catalyzed by this enzyme?

How Do You Stop an Enzyme? Denaturation: • The process of changing the shape of a enzyme thus destroying its function •Caused by heat or pH Irreversible egg protein denaturation caused by high temperature (while cooking it).

Factors Affecting Enzyme Activity Temperature pH Cofactors & Coenzymes Inhibitors

Coenzymes & Cofactors Non-protein substances (zinc, iron, copper, vitamins) are sometimes needed for proper enzymatic activity. Example of enzyme cofactor : Ribbon-diagram showing carbonic anhydrase II. The grey sphere is the zinc cofactor in the active site.

Catecholase Catecholase is present in most fruits and vegetables. It is the enzyme that facilitates the browning of cut or bruised fruits and vegetables by catalyzing the following reaction: (catecholase) catechol + oxygen ----------------- polyphenol colorless substrate brown product

So what happened to the apple slice? Lemon juice and other acids are used to preserve color in fruit, particularly apples, by lowering the pH and removing the copper site (cofactor) necessary for the enzyme to function. catecholase catechol + O2 -------------------------- polyphenol colorless substrate brown product So what happens to catecholase when you add an acid (lemon juice) to the apple slice?

Two Types of Enzyme Inhibitors 1. Competitive inhibitors: Chemicals that resemble an enzyme’s normal substrate and compete with it for the active site. Example: Methotrexate is used in chemotherapy and inhibits an enzyme involved in DNA replication (a process necessary for cell division) Substrate

Two Types of Enzyme Inhibitors Noncompetitive inhibitors: Do not enter the active site, but bind to another part of the enzyme causing the enzyme to change its shape, altering the active site. Substrate active site altered

Enzyme Inhibitors Blocking an enzyme's activity can kill a pathogen or correct a metabolic imbalance. Many drugs are enzyme inhibitors. Enzymes are also used as pesticides and herbicides.

Overview of Mammalian Digestive Enzymes