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Enzymes

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What Are Enzymes?• Most enzymes

are Proteins (tertiary and quaternary structures)

• Act as Catalyst to accelerates a reaction

• Not permanently changed in the process

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Enzymes• Are specific

for what they will catalyze

• Are Reusable• End in –ase

-Sucrase-Lactase-Maltase

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How do enzymes Work?Enzymes work by weakening bonds which lowers activation energy

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Enzymes

FreeEnergy

Progress of the reaction

Reactants

Products

Free energy of activation

Without EnzymeWith Enzyme

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Enzyme-Substrate ComplexThe substance

(reactant) an enzyme acts on is the substrate

EnzymeSubstrate Joins

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Active Site• A restricted region of an enzyme

molecule which binds to the substrate.

EnzymeSubstrate

Active Site

ENZYME ACTION• http://highered.mcgraw-hill.com/sites/0072495855/student_view0/

chapter2/animation__how_enzymes_work.html

Enzyme Substrate Complex (Induced Fit)

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1. Environmental Conditions 1. Extreme Temperature are the

most dangerous- high temps may denature (unfold) the enzyme.

2. pH (most like 6 - 8 pH near neutral)3. Ionic concentration (salt ions)

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2. Cofactors and Coenzymes• Inorganic substances (zinc, iron) and

vitamins (respectively) are sometimes need for proper enzymatic activity.

• Example:Iron must be present in the

quaternary structure - hemoglobin in order for it to pick up oxygen.

ENZYME DEFICIENCY AND HEALTH

Most genetic disorders are due to a deficiency in enzyme function.

This archival photo shows three children with the enzyme deficiency that causes phenylketonuria.

What is it?Phenylketonuria (PKU) is a hereditary disease that is caused by the lack of a liver enzyme required to digest phenylalanine. Phenylalanine is an amino acid that is most commonly found in protein-containing foods such as meat, cow's milk, over the counter infant formulas (both regular and soy) and breast milk.

Signs & SymptomsNewborns affected by PKU usually do not show any signs of the disease at birth. But within the first few weeks of life they begin to show neurologic disturbances such as epilepsy. Signs also include skeletal changes such as a small head, short stature, and flat feet. PKU sufferers may also have a skin disorder called eczema.Long Term EffectsPKU-affected children who are not diagnosed and do not eliminate phenylalanine from the diet will suffer from irreversible brain damage and mental retardation. Properly treated individuals should live a normal, healthy life.TreatmentTreatment of PKU is the elimination of phenylalanine from the diet. Phenylalanine is commonly found in protein-containing foods such as meat. Babies who are diagnosed with PKU must immediately be put on a special milk/formula substitute. Later in life, the diet is mainly vegetarian.

http://www.youtube.com/watch?v=CZD5xsOKres