digestion of biomolecules - indiana university...
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![Page 1: Digestion of Biomolecules - Indiana University Bloomingtoncourses.chem.indiana.edu/c383/documents/Lecturech14.pdf · Chapter 14. Hydrolysis Reactions •Proteins amino acids –Proteases,](https://reader031.vdocuments.site/reader031/viewer/2022030621/5ae851537f8b9acc268ff348/html5/thumbnails/1.jpg)
Digestion of Biomolecules
Stryer Short courseChapter 14
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Hydrolysis Reactions
• Proteins amino acids– Proteases, peptidases
• Complex carbohydrates monosaccharides– amylase
• Triacylglycerides fatty acids– lipase
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Zymogens
• Proenzymes—inactive precursors• Cannot release digestive enzymes everywhere!
• Pepsinogen pepsin: autocatalysis at low pH
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Pancreatic Zymogens
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Mechanism
• Protease activates trypsin
• Trypsin activates other zymogens
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Stomach
• Highly acidic, denaturing environment
• Pepsin begins work• Acidic, partially digested food enters intestine– Activates secretin to neutralize adic
– Activates hormone causing release of pancreatic zymogens and bile salts
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Stomach acid
• Prilosec: irreversible inhibitor of proton, potassium pump
Error in carbonic anhydrase
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Proteins in the Intestine
• Protein digestion continues with proteases in lumen• Transporter proteins essential—basis of some genetic diseases
• Amino acids then sent to liver• Gluten sensitivity
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Carbohydrates in the Intestine
• ‐amylase• Limiting dextrins• Maltase, sucrose, lactase, glucosidase, dextrinase all work to digest to monosaccharides
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Carbohydrate Transporters
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Lipid Digestion
• Complicated by insolubility
• Emulsion form in stomach
• Extra steps of degradation/re‐assembly
• Bile salts– Cholesterol lowering medications
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Pancreatic Lipases
• Zymogens• Fatty acids and MAG• Miscelle formation
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Transport to Liver
• Fatty acid binding proteins
• Fatty acid transport proteins
• Smooth enoplasmicreticulum
• chylomycrons