Enzymes

Chemical reactions Definition: Any process in which a chemical change occurs Chemical change: a process in which a substance is permanently altered

Chemical reactions Always involves a change in the properties and in the energy of the substances involved

Chemical reaction Described in a shorthand method known as a chemical equation Symbols and formulas are used to represent reactants and products An arrow, which is read “yields” shows the direction of the reaction

Chemical Reaction Oxygen plus hydrogen yields water O 2 + 2H 2  2H 2 O Both of the above represent the same reaction (rxn.) One is given in words; the other in chemical equation

Identifying parts of a chemical rxn. Reactants-the substances changed during a chemical reaction Oxygen and hydrogen Products-the substances made by the chemical reaction Water The arrow points to products!!

Chemical Reaction Cellular Respiration: 6O 2 + C 6 H 12 O 6  6CO 2 + 6H 2 0 Oxygen and Glucose yields carbon dioxide and water

Reversible Reactions Some reactions can take place in both directions. Forward and backward In these cases, the products and reactants would switch roles.

Two main types of reactions Endothermic – absorbs heat and feels cold to touch Exothermic – releases heat and feels warm/hot to touch

Vocabulary Catalyst- A substance that speeds up a reaction but does not become part of the reaction Substrate- A substance acted upon by an enzyme Protein- a large molecule used in building tissue Active Site- the location of a reaction between an enzyme and a substrate

Characteristics of enzymes 1.Proteins that act as biological catalysts 2.Specific to the substrate they act upon Example: lactose is broken down by Lactase and sucrose is broken down only by sucrase 3. Many end with the suffix –ase 4. Associated primarily with digestion

1. An enzyme and a substrate are in the same area. The substrate is the biological molecule that the enzyme will attack. 2. The enzyme grabs onto the substrate with a special area called the active site The active site is a specially shaped area of the enzyme that fits around the substrate. The active site is the keyhole of the lock. 3. A process called catalysis happens. Catalysis is when the substrate is changed. It could be broken down or combined with another molecule to make something new. 4. The enzyme lets go. Big idea. When the enzyme lets go, it returns to normal, ready to do another reaction. The substrate is no longer the same. The substrate is now called the product.

Enzymes sometimes need to be controlled. Other times they are controlled because of poisons and contaminants. So what affects enzyme activity? 1.Temperature: Proteins (enzymes) change shape with temp change…since activity is dependant on shape – the enzyme will no longer work – This is called denaturization. 2.Activators: speed up enzyme activity to make the reaction faster 3.pH: same effect as temp 4.Inhibitors: opposite of activator 5.Concentration: Increase enzyme conc., rate of rxn increases. If you decrease conc, then the rate decreases.

Digestive Enzymes SiteEnzymeRole in digestion MouthSalivary amylase Breaks down starches StomachPepsinBreaks down proteins Small intestine from pancreas Amylase, trypsin, lipase Starch, protein, fat Small intestineMaltase, sucrase, lactase Breaks down sugars

Roll of Enzymes in Bread: Fungal Amylase produce reducing sugars helps in color of final loaf of Bread. Also it gives better handling properties & fine crumb Structure. Improves Elasticity. Gives better volume. Less tough dough. Improve volume. Softness in Crumb. Shelf life. Bleaching effect. Improved Crumb Structure due to lipid protein interaction

Enzymes in fruit juice Fruit cell wall consists of various polysaccharides and proteins. In olden days fruit juice was extracted from cell wall by physically macerating the fruit. This can be achieved in better way by enzymes in terms of yield and clarification. Research in the field of Fruit Juice Processing says that the quality of juice manufactured and its stability has been improved by use of enzymes. (In terms of Characteristic, Taste, and Flavor).

Enzymes in detergents Since last 40 years, the use of enzymes in detergents has been the largest of all enzyme applications. Consumers of detergents are actual users of an enzymatic product. In majority of other applications, enzymes are used as auxiliary agents at some point in the manufacturing process and are not, as a rule, present in the finished product - not at any rate in an active form. Proteases are the most widely used enzymes in the detergent industry. They remove protein stains such as grass, blood, egg and human sweat.