Section 2.5 Key Concept: Enzymes lower the activation energy for chemical reactions in living things

What Are Enzymes? Enzymes are a special group of protein molecules which speed up chemical rxns in living cells by lowering the activation energy (E A )

Fun Facts about Enzymes Make rxns go 10 trillion times faster – 1500 yrs vs. 5 seconds Are not living Are reusable There are about 2000 different enzymes in each one of your cells Names usually end in -ase

How do enzymes work? Each enzyme has a unique 3-D shape, including a surface groove called an ACTIVE SITE. One or more molecules called SUBSTRATES chemically bond to the enzyme’s active site. When joined they are called an ENZYME-SUBSTRATE COMPLEX Changes in how the atoms are bonded occur resulting in new molecules being made called PRODUCTS. Products are then released from the active site.

How enzymes make rxns go faster Enzymes work by reducing the amount of energy needed (E A ) for the bonds in the substrate molecules to break

Enzyme-Substrate Complex enzyme The reactant an enzyme acts on is specifically called the _________. Enzyme Substrate Joins

______ _____ enzyme substrateA specific region of an enzyme molecule which binds to the substrate. Enzyme Substrate Active Site

EnzymeAnimation : Gary E. Kaiser View : hill.com/sites/ /student_view0/chapter2/animation__how_enzymes_work.htmlhttp://student.ccbcmd.edu/biotutorials/proteins/enzsub.html

An enzyme flick Let the show begin....

General Types of Enzymes Amylases – break starch to glucose Lipases – break lipids to fatty acids and glycerol Proteases – break proteins to amino acids Nucleases – break nucleic acids DNA and RNA to nucleotides

Shape of a Protein An enzyme fits with its specific substrate like a “lock and key”

How Do You Stop an Energizer Enzyme?

DENATURE IT! Means it loses its 3D shape

4 levels of Protein Structure

Factors Affecting Enzyme Activity Temperature pH Cofactors & Coenzymes Inhibitors

Temperature & pH Enzymes work best at specific temperatures This is why very high fevers are so dangerous. They can cook the body’s proteinsThis is why very high fevers are so dangerous. They can cook the body’s proteins Enzymes usually work best between pH 6 - 8

Coenzymes & Cofactors Molecules that are needed by the enzyme to work properly. substances (zinc, iron, copper, vitamins ) Many are vitamins and mineral substances (zinc, iron, copper, vitamins ) Image: EnzymeCofactor : Public domain Wiki, Ribbon-diagram showing carbonic anhydrase II. The grey sphere is the zinc cofactor in the active site.

Diseases due to enzyme damaged or missing Lactose intolerance Phenylketonuria Lacking lactase Phenylalanine hydroxylase

Enzyme Inhibitors resembleenzyme’s normal substrate compete active site Chemicals that resemble an enzyme’s normal substrate and compete with it for the active site. Enzyme Competitive inhibitor Substrate

1. Competitive inhibitors: esembleenzyme’s normal substrate compete active site Resemble an enzyme’s normal substrate and compete with it for the active site. Image: Competitive Inhibition : www- biol.paisley.ac.uk/.../chapter3_2.htmlwww- biol.paisley.ac.uk/.../chapter3_2.html

Inhibitors can also attach to another part enzymeenzyme change the shape of its active site. Inhibitors can also attach to another part of the enzyme causing the enzyme to change the shape of its active site. If its shape changes..it no longer works! If its shape changes..it no longer works! Enzyme active site altered Noncompetitive Inhibitor Substrate

Enzyme Inhibitors Blocking an bacteria’s enzymes can kill it Many antibiotic drugs are enzyme inhibitors. Enzyme inhibitors are also used as weed and bug killers Images Dead Bug : Prescription Drugs : noon.html

Enzymes are ____ ________ in the reactions they catalyze. Think of them as tiny machines in manufacturing. The more machines, the faster the accumulation of _________. Image: Wine Bottling : Wine Vats:

Formats for writing a chemical reaction. ( ________ ) _______ + ________ > _________ ( ________ ) __________ > ________ ________

Coenzyme : Vitamin B12 Example :Example : Most _________ are coenzymes essential in helping move atoms between molecules in the formation of carbohydrates, fats, and proteins. Exclusively synthesized by ___________ (found primarily in meat, eggs and dairy products). Image: VitaminB12 : NIH, Public Domain

Featured Enzyme #1: Catecholase Catecholase is present in most ______ and __________. It is the enzyme that facilitates the ________ of cut or bruised fruits and vegetables by catalyzing the following reaction: (______________) _________ + _____  _____________ colorless substrate brown product

Featured Enzyme #1: Catecholase & Noncompetetive Inhibition _________ juice and other acids are used to preserve color in fruit, particularly apples, by lowering the ____ and removing the copper site (cofactor) necessary for the enzyme to function. catecholase catechol + O  polyphenol colorless substrate brown product

Featured enzyme #2: Bromelain Pineapple contains enzyme bromelain, which can _______ _________. Jell-O is made of gelatin, a processed version of a structural protein called _________ that is found in many animals, including humans. Collagen big, fibrous molecule makes skin, bones, and tendons both strong and elastic. Gelatin you eat in Jell-O comes from the collagen in cow or pig bones, hooves, and connective tissues. (Yummie!) Examine 2 containers: a. In one, canned pineapple was used to make jello. b. The other, fresh pineapple was used.

bank.com/iwb/flash/enzymetale. html