Protein: Amino AcidsProtein: Amino Acids
Chapter 6Chapter 6
Amino AcidAmino Acid
“R”
Amino AcidsAmino Acids• Essential amino acidsEssential amino acids
– i.e. indispensable amino acidsi.e. indispensable amino acids– PVT. TIM HALL (or PVT. MAT HILL)PVT. TIM HALL (or PVT. MAT HILL)
• Nonessential amino acidsNonessential amino acids– i.e. dispensable amino acidsi.e. dispensable amino acids
• ““Conditionally” essential amino acidsConditionally” essential amino acids
An Essential Amino AcidAn Essential Amino Acid
Nonessential Amino AcidsNonessential Amino Acids
ProteinsProteins
• DipeptideDipeptideRemember Condendation?Remember Condendation?
• Tripeptide: Yes...it’s three of ‘em.Tripeptide: Yes...it’s three of ‘em.
ProteinsProteins• PolypeptidePolypeptide
ProteinsProteins• Amino acid sequencesAmino acid sequences
– With 20 different amino acids you With 20 different amino acids you can say a lot!can say a lot!
Protein Protein shape shape and and
functionfunction
ProteinsProteins• Protein Protein denaturationdenaturation
– uncoilinguncoiling• heat or acid hydrolysis.heat or acid hydrolysis.
– loss of functionloss of function
Protein DigestionProtein Digestion• StomachStomach
– HCl activated pepsinogen HCl activated pepsinogen (proteolytic enzyme)(proteolytic enzyme)
– Pepsinogen* Pepsinogen* pepsin pepsin – Pepsin hydrolyzes proteins!Pepsin hydrolyzes proteins!
**ProenzymeProenzyme-an inactive form of enzyme!-an inactive form of enzyme!
Protein DigestionProtein Digestion• Small intestineSmall intestine
– Proteases-more hydrolysis!Proteases-more hydrolysis!•Intestinal and pancreaticIntestinal and pancreatic
– PeptidasesPeptidases
Protein Protein Digestion in Digestion in the GI Tractthe GI Tract
Protein AbsorptionProtein Absorption• CarriersCarriers
• CapillariesCapillaries
• Absorption misconceptionsAbsorption misconceptions– Enzyme/amino acid supplementsEnzyme/amino acid supplements
Protein SynthesisProtein Synthesis• Sequencing errorsSequencing errors
Roles of ProteinsRoles of Proteins• Building materialBuilding material
– GrowthGrowth– MaintenanceMaintenance
Roles of ProteinsRoles of Proteins• EnzymesEnzymes
Roles of ProteinsRoles of Proteins
• HormonesHormones
Roles of ProteinsRoles of Proteins• Regulation of fluid balanceRegulation of fluid balance
– EdemaEdema
• Acid-base regulationAcid-base regulation– AcidosisAcidosis– AlkalosisAlkalosis
Transport ProteinsTransport Proteins
One of the most important One of the most important proteins in your body!proteins in your body!
The Sodium-Potassium The Sodium-Potassium Pump in action!Pump in action!
Roles of ProteinsRoles of Proteins• ImmunityImmunity
– AntibodiesAntibodies– AntigensAntigens
Protein MetabolismProtein Metabolism• Protein turnoverProtein turnover
– Amino acid poolAmino acid pool
• Nitrogen balanceNitrogen balance– Positive nitrogen balancePositive nitrogen balance– Negative nitrogen balanceNegative nitrogen balance
Protein MetabolismProtein Metabolism• Using amino acids to make Using amino acids to make
proteinsproteins
• Using amino acids to make Using amino acids to make nonessential amino acidsnonessential amino acids
Protein MetabolismProtein Metabolism• Using amino acids to make other Using amino acids to make other
compoundscompounds– NeurotransmittersNeurotransmitters
Protein MetabolismProtein Metabolism• Using amino acids for energy and Using amino acids for energy and
glucoseglucose
• Deamination-removal of NHDeamination-removal of NH33
• Using amino acids to make fatUsing amino acids to make fat
Protein QualityProtein Quality• High-quality proteinsHigh-quality proteins
• DigestibilityDigestibility– Animal (90%) vs. plant (70%)Animal (90%) vs. plant (70%)
• Amino acid compositionAmino acid composition– Limiting amino acidLimiting amino acid
Protein QualityProtein Quality
• Reference proteinReference protein
• Complementary proteinsComplementary proteins
Protein QualityProtein Quality
• PDCAASPDCAAS– Protein- Protein-
digestibility-digestibility-corrected-amino- corrected-amino- acid-scoreacid-score
Protein-Energy Protein-Energy Malnutrition (PEM)Malnutrition (PEM)
• Acute PEMAcute PEM
• Chronic PEMChronic PEM
Protein-Energy Protein-Energy Malnutrition (PEM)Malnutrition (PEM)
• MarasmusMarasmus
• KwashiorkorKwashiorkor
• Marasmus-kwashiorkor mixMarasmus-kwashiorkor mix
Protein-Energy Protein-Energy Malnutrition (PEM)Malnutrition (PEM)
• InfectionsInfections– DysenteryDysentery
• Rehabilitation-can they recover?Rehabilitation-can they recover?
Health EffectsHealth Effects• Heart diseaseHeart disease
• CancerCancer
• Adult bone lossAdult bone loss– osteoporosisosteoporosis
Health EffectsHealth Effects• Weight controlWeight control
• Kidney disease?Kidney disease?
Recommended Recommended IntakesIntakes
Daily ValueDaily Value
– 50 g protein50 g protein•10% of a 2000 kcal diet10% of a 2000 kcal diet
• RDARDA– 0.8 g/kg/day0.8 g/kg/day– 10% - 35% of energy intake10% - 35% of energy intake
Recommended Recommended IntakesIntakes
• Adequate intakeAdequate intake
• Protein in abundanceProtein in abundance
SupplementsSupplements• Protein supplementsProtein supplements
• Amino acid supplementsAmino acid supplements
Vegetarian DietsVegetarian Diets
Vegetarian DietsVegetarian Diets• Diet planningDiet planning
– ProteinProtein•Lacto-ovo-vegetariansLacto-ovo-vegetarians•Meat replacementsMeat replacements
–Texturized vegetable Texturized vegetable protein-basically soybeansprotein-basically soybeans
Vegetarian DietsVegetarian Diets• Vitamins and mineralsVitamins and minerals
– Lactovegetarians-easier to meet Lactovegetarians-easier to meet calcium/vit. D requirementscalcium/vit. D requirements
– Vegans-supplements likely needed.Vegans-supplements likely needed.
– Omega-3 fatty acids also needed.Omega-3 fatty acids also needed.
Vegetarian DietsVegetarian Diets• Vegetarian diets through the life Vegetarian diets through the life
spanspan– Pregnancy and lactationPregnancy and lactation– InfancyInfancy– Childhood and adolescenceChildhood and adolescence
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