Transcript Document
ENZYMES & Chemical Digestion Chemical Digestion Basics • Dehydration Synthesis vs. Hydrolysis • Anabolic – Dehydration Synthesis – Require the removal of water to form bonds • Catabolic – Hydrolytic Reactions – Require the addition of water to break bonds • Carbohydrates – mono and disaccharides • Lipids (triglycerides) – glycerol + fatty acids • Proteins – amino acids substrate enzyme enzyme Terminology: •Enzyme •Active site •Substrate(s) •Product(s) •Reversible reactions products Factoids: Enzymes are: • Proteins Factoids: Enzymes: • Lower the activation energy needed for a reaction to take place A + B Molecule C Factoids: Enzymes: • Are unchanged after catalyzing a reaction Factoids: Enzymes: • Turnover numbers are very high • Examples: – 1 molecule of acetylcholinesterase -> 25,000 molecules of acetylcholine in 1 second – 1 molecule of catalase breaks down 40 million molecules of hydrogen peroxide in 1 second Factoids: Enzymes: • Are specific in their activity • Lock and key model Factoids: Enzymes: • Sometimes require a nonprotein factor = cofactor (metallic ion) or coenzyme (vitamin) – Examples: • Iron, zinc, copper, sodium, potassium, vitamin B Factoids: Enzymes: • are usually named after the substrate on which they act • have names ending in –ase ( with a few exceptions) Examples: • Cellulase • Sucrase • Lipase • Lactase • Acetylcholinesterase Factors Affecting Enzyme Activity Temperature more H+ Pepsin – stomach enzyme Trypsin – duodenum enzyme pH Concentration of Enzyme or Substrate Inhibitors • Competitive Inhibition • Noncompetitive Inhibition Enzyme Uses Papaya and Papain Pineapple and Bromelain Lactose = milk sugar • Lactase – enzyme produced by cells that line the small intestine • Symptoms • Solutions – Avoid dairy products (calcium problem) and prepared foods containing lactose – Determine problematic amounts of lactose or source (i.e. milk, ice cream, aged cheeses) – Lactase additives: add to milk (lactose content reduced by 70% or buy lactose-reduced milk Enzyme Dietary Supplements Questions Concerning Dietary Enzyme Supplements • Are there people who do not produce enough of certain enzymes? • Could an increase in digestive enzymes increase the digestion of food? • Can you increase the amount of digestive enzymes by taking oral dietary supplements?