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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
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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
Terminology: • Enzyme • Active site • Substrate(s) • Product(s) • Reversible reactions substrate enzyme products enzyme
Factoids: Enzymes are: • Proteins
B + A Factoids: Molecule C Enzymes: • Lower the activation energy needed for a reaction to take place
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
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 Factoids:
pH more H+ Pepsin – stomach enzyme Trypsin – duodenum enzyme
Inhibitors • Competitive Inhibition • Noncompetitive Inhibition
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
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?