© 2006 thomson-wadsworth protein: amino acids. © 2006 thomson-wadsworth amino acids

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© 2006 Thomson-Wadsworth Protein: Amino Acids

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© 2006 Thomson-Wadsworth

Protein: Amino Acids

© 2006 Thomson-Wadsworth

Amino Acids

© 2006 Thomson-Wadsworth

Amino Acids

• Nonessential amino acids– a.k.a dispensable amino acids

• Essential amino acids– a.k.a indispensable amino acids

• Conditionally essential amino acids

© 2006 Thomson-Wadsworth

© 2006 Thomson-Wadsworth

An Essential Amino Acid

© 2006 Thomson-Wadsworth

Nonessential Amino Acids

© 2006 Thomson-Wadsworth

Proteins

• Peptide bond

© 2006 Thomson-Wadsworth

Proteins

• Dipeptide

© 2006 Thomson-Wadsworth

Proteins

• Tripeptide

© 2006 Thomson-Wadsworth

Proteins

• Polypeptide

© 2006 Thomson-Wadsworth

Proteins

• Amino acid sequences

© 2006 Thomson-Wadsworth

• Protein shape and function

© 2006 Thomson-Wadsworth

Proteins

• Protein denaturation

© 2006 Thomson-Wadsworth

Protein Digestion

• Stomach– HCl– Pepsinogen pepsin

•Proenzyme

© 2006 Thomson-Wadsworth

Protein Digestion

• Small intestine– Proteases

•Intestinal and pancreatic– Peptidases

© 2006 Thomson-Wadsworth

© 2006 Thomson-Wadsworth

Protein Absorption

• Carriers

• Capillaries

• Absorption misconceptions– Enzyme/amino acid supplements

© 2006 Thomson-Wadsworth

Protein Synthesis

• Delivering the instructions– DNA

•mRNA

© 2006 Thomson-Wadsworth

Protein Synthesis

© 2006 Thomson-Wadsworth

Protein Synthesis

© 2006 Thomson-Wadsworth

Protein Synthesis

© 2006 Thomson-Wadsworth

Protein Synthesis

• Sequencing errors

© 2006 Thomson-Wadsworth

© 2006 Thomson-Wadsworth

Protein Synthesis

• Nutrients and gene expression

© 2006 Thomson-Wadsworth

Roles of Proteins

• Building material– Growth– Maintenance

© 2006 Thomson-Wadsworth

Roles of Proteins

• Enzymes

© 2006 Thomson-Wadsworth

Roles of Proteins

• Hormones

© 2006 Thomson-Wadsworth

Roles of Proteins

• Regulation of fluid balance– Edema

• Acid-base regulation– Acidosis– Alkalosis

© 2006 Thomson-Wadsworth

• Transport proteins

© 2006 Thomson-Wadsworth

Roles of Proteins

• Immunity– Antibodies– Antigens

© 2006 Thomson-Wadsworth

Roles of Proteins

• Source of energy

• Other roles

© 2006 Thomson-Wadsworth

Protein Metabolism

• Protein turnover– Amino acid pool

• Nitrogen balance– Positive nitrogen balance– Negative nitrogen balance

© 2006 Thomson-Wadsworth

Protein Metabolism

• Using amino acids to make proteins

• Using amino acids to make nonessential amino acids

© 2006 Thomson-Wadsworth

Protein Metabolism

• Using amino acids to make other compounds– Neurotransmitters

• Using amino acids for energy and glucose

© 2006 Thomson-Wadsworth

Protein Metabolism

• Deamination

• Using amino acids to make fat

© 2006 Thomson-Wadsworth

Protein Quality

• High-quality proteins

• Digestibility– Animal vs. plant

• Amino acid composition– Limiting amino acid

© 2006 Thomson-Wadsworth

Protein Quality

• Reference protein

• Complementary proteins

© 2006 Thomson-Wadsworth

Protein Quality

• PDCAAS– Protein

digestibility-corrected amino acid score

© 2006 Thomson-Wadsworth

Food Labels

• Quantity of protein

• Daily Value– 50 g protein

•10% of a 2000 kcal diet

© 2006 Thomson-Wadsworth

Protein-Energy Malnutrition (PEM)

• Acute PEM

• Chronic PEM

© 2006 Thomson-Wadsworth

Protein-Energy Malnutrition (PEM)

• Marasmus

• Kwashiorkor

• Marasmus-kwashiorkor mix

© 2006 Thomson-Wadsworth

© 2006 Thomson-Wadsworth

© 2006 Thomson-Wadsworth

Protein-Energy Malnutrition (PEM)

• Infections– Dysentery

• Rehabilitation

© 2006 Thomson-Wadsworth

Health Effects

• Heart disease

• Cancer

• Adult bone loss– osteoporosis

© 2006 Thomson-Wadsworth

Health Effects

• Weight control

• Kidney disease

© 2006 Thomson-Wadsworth

Recommended Intakes

• RDA– 0.8 g/kg/day– 10% - 35% of energy intake

© 2006 Thomson-Wadsworth

Recommended Intakes

• Adequate intake

• Protein in abundance

© 2006 Thomson-Wadsworth

Supplements

• Protein supplements

• Amino acid supplements

© 2006 Thomson-Wadsworth

Vegetarian Diets

© 2006 Thomson-Wadsworth

Vegetarian Diets

• Health benefits

© 2006 Thomson-Wadsworth

Vegetarian Diets

• Diet planning– Protein

•Lacto-ovo-vegetarians•Meat replacements

–Texturized vegetable protein

© 2006 Thomson-Wadsworth

Vegetarian Diets

• Vitamins and minerals– Lactovegetarians– Vegans

© 2006 Thomson-Wadsworth

Vegetarian Diets

• Omega-3 fatty acids

© 2006 Thomson-Wadsworth

Vegetarian Diets

• Vegetarian diets through the life span– Pregnancy and lactation– Infancy– Childhood and adolescence

© 2006 Thomson-Wadsworth

Vegetarian Diets

• Healthy food choices– Macrobiotic diets