C-Notes: Enzymes

C-Notes: EnzymesStnd: BI.1b 9/9/13

Objective:

SWBAT recognize that enzymes are proteins that catalyze biochemical reactions in cells.

What are Enzymes?Helper protein molecules

Are PROTEINS that acts as biological catalyst to speed up chemical reaction in living cells.(catalyst/catalyze/catalase the action of enzymes to speed up a chemical reaction in living cells)

Flow of energy through lifeLife is built on chemical reactions

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How do Enzymes function (work) in a cell ?

Building molecules

2. Breaking down molecules They do almost ALL the work within a cell.

**It decreased activation energy and increase reaction rate. **enzyme++enzymeWe cant live without enzymes!

Examples synthesisdigestion++enzymeenzymeenzymeenzyme5

How does the structure of an enzyme affect its function?

Enzymes are SPECIFIC!Each enzyme has a SPECIFIC SHAPE that only allows for a certain reactant to bind to it. (needs to be the RIGHT SHAPE for the job)2. Enzymes are REUSABLE! B/C they are not used up or changed by the reaction when breaking down a substrate and can perform the same action over and over very quickly.

The specific reactant that enzymes binds to is called SUBSTRATE (food & waste) .

Substrates binds to specific places on an enzyme called active sites Ex: Protease (Enzymes) only breaks down (binds to) proteins (substrate) to form amino acids productEx: protease + protein Amino Acids (Enzyme) (substrate) (product)

You can recognize enzymes b/c it ends in aseEnzymes are named for the reaction the help! Ex: Lactase breakdown lactose in milk Protease breakdown proteins Lipase breakdown lipids(Enzymes) (Macromolecules)

Other terms you need to knowSubstrate the substance that the enzyme works on e.g. Lipase the substrate is lipidsProduct the substance that is made by the reaction e.g. Breakdown of Lipids by Lipase the product is __________________Fatty acids & glycerol

What are the Two Types of Active Sites (shape) model? Lock & Key model (shape specific)Substrate & enzyme fit together PERFECTLY.

Induced-Fit ModelEnzyme itself changes shape by Stretching and bending to fit the substrate.

Model of Lock and Keyproductssubstrateenzymeenzyme unchangedactive siteenzyme substrate complex

What are the factors that affects enzymes activity (rate of reaction)?Correct protein structureTemperature pH (acids and bases) levelConcentration of enzyme and substrate

DNADNAchain ofamino acidschain ofamino acidsfoldedproteinfoldedproteinright shape!wrong shape!

Wrong order wrong shape cant do its job1. How does the order of amino acid (Protein structure) affect enzyme reaction (activity)?

Ideal temperature (WORKS BEST)35- 40C (body temp = 37C)greater numbers of collisions between enzyme & substrateRaised temperature (Hot)denature protein unfold loses its shapeLowered temperaturemolecules move slower fewer numbers of collisions between enzyme & substrate

2. How does the Temperatureaffect enzyme reaction?37

Temperature temperaturereaction rate

Whats happening here?!humanenzymes13

Affects on rates of enzyme reaction (activity) **changes in pH level changes protein shape**most human enzymes pH 6-8 (depends on where in body)Ex: pepsin (stomach) = pH 3trypsin (small intestines) = pH 8

**Extremes in acid and base (pH level) will unravel or denature the enzyme**

** Each enzyme has an ideal temperature and pH**

3. How does the pH level(acids & bases) affect enzyme reaction?The pH ScaleThe pH scale measures whether a solution is acid, basic or neutral.The scale runs from 0 to 14.A pH of 7 indicates that the solution is neutral.This means that the solution is neither an acid nor a base.

4. How does concentration of enzymes and substrate affects enzymes reactions?Increase substrate will slowdown the reaction rateIncrease enzyme will not speed up the rate of reaction**How fast a chemical reaction take places, depends on how much of the substrate & enzymes is available**

What are the structures of proteins? Proteins are made of chains of AMINO ACIDS. There are only 20 amino acids and can be combined in nearly countless ways. The sequence of amino acids determines the shape of the protein. The shape of the protein is the biggest factor that determines its function.

There are 4 levels of structurePrimary structureLinear shape (straight line) Secondary structure (2 types)Folding of protein structure-helix (spiral shape) and -sheets (folded shape)Tertiary structure actual 3D shapeQuaternary structureWhen 2 or more smaller polypeptides w/ different shapes join together.

Any alteration in the structure or sequencing changes the shape and function of the protein

Amino acidsubunitsb pleated sheet helixSecondary Protein Structure

Amino acidsubunitsb pleated sheet helix

LE 5-20eb Chainsa ChainsHemoglobinIron

Heme

Collagen

Polypeptide chain

Polypeptidechain

What happens when enzymes (proteins) Denature? Because proteins shape are affected by temperature and pH changes. It loses its normal shape when it is not in ideal optimal environmental conditions. When a protein loses its normal shape, this is called denaturing.A denatured protein is biologically INACTIVE.Denaturing is usually permanent and not reversible.

Denaturing a ProteinFigure 6.5

2009-2010For enzymesWhat matters?SHAPE!

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Structural Differences Between Carbohydrates, Lipids, and ProteinsFigure 6.1