Title: Protein: Amino Acids
1Protein Amino Acids
2The Chemists View of Proteins
- Atoms
- Carbon, hydrogen, oxygen, nitrogen
- Amino acids
- Carbon
- Hydrogen
- Amino group
- Acid group
- Side group or side chain
3The Chemists View of Proteins
4The Chemists View of Proteins
- More complex than carbohydrates or fats
- Twenty amino acids
- Different characteristics
- Essential amino acids
- Nonessential amino acids
- Conditionally essential
5The Chemists View of Proteins
6The Chemists View of Proteins
- Proteins
- Peptide bonds link amino acids
- Condensation reactions
- Amino acid sequencing
- Primary structure chemical bonds
- Secondary structure electrical attractions
- Tertiary structure hydrophilic hydrophobic
- Quaternary structure two or more polypeptides
7The Chemists View of Proteins
8The Chemists View of Proteins
- Protein
- Denaturation
- Disruption of stability
- Uncoil and lose shape
- Stomach acid
9Protein Digestion
- Mouth
- Stomach
- Hydrochloric acid denatures proteins
- Pepsinogen to pepsin
- Small intestine
- Hydrolysis reactions
- Peptidase enzymes
10Protein Digestion
11Protein Absorption
- Transport into intestinal cells
- Uses of amino acids by intestinal cells
- Unused amino acids transported to liver
- Enzyme digestion
- Predigested proteins
12Protein Synthesis
- Uniqueness of each person
- Amino acid sequences of proteins
- Genes DNA
- Diet
- Adequate protein
- Essential amino acids
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14Protein Synthesis
- DNA template to make mRNA
- Transcription
- mRNA carries code to ribosome
- Ribosomes are protein factories
- mRNA specifies sequence of amino acids
- Translation
- tRNA
- Sequencing errors
15Protein Synthesis
16Protein Synthesis
- Gene expression and protein synthesis
- Capability of body cells
- Protein needs
- Dietary influence on gene expression
- Disease development
17Roles of Proteins
- Growth and maintenance
- Building blocks for most body structures
- Collagen
- Replacement of dead or damaged cells
- Enzymes
- Break down, build up, and transform substances
- Catalysts
18Roles of Proteins
19 The separate compounds, A and B, are attracted to
the enzymes active site, making a reaction
likely.
The enzyme forms a complex with A and B.
The enzyme is unchanged, but A and B have formed
a new compound, AB.
Stepped Art
Fig. 6-9, p. 181
20Roles of Proteins
- Hormones
- Messenger molecules
- Transported in blood to target tissues
- Regulators of fluid balance
- Edema
- Acid-base regulators
- Attract hydrogen ions
- Transporters specificity
21Roles of Proteins
22Roles of Proteins
- Antibodies
- Defend body against disease
- Specificity
- Immunity memory
- Energy and glucose
- Starvation and insufficient carbohydrate intake
- Other roles
23Preview of Protein Metabolism
- Protein turnover amino acid pool
- Continual production and destruction
- Amino acid pool pattern is fairly constant
- Used for protein production
- Used for energy if stripped of nitrogen
- Nitrogen balance
- Zero nitrogen balance
- Positive and negative nitrogen balance
24Preview of Protein Metabolism
- Making other compounds
- Neurotransmitters
- Melanin
- Thyroxin
- Niacin
- Energy and glucose
- Wasting of lean body tissue
- Adequate intake of carbohydrates and fats
25Preview of Protein Metabolism
- Making fat
- Energy and protein exceed needs
- Carbohydrate intake is adequate
- Can contribute to weight gain
- Deaminating amino acids
- Stripped of nitrogen-containing amino group
- Ammonia
- Keto acid
26Preview of Protein Metabolism
- Make proteins nonessential amino acids
- Breakdown of proteins
- Keto-acids
- Liver cells and nonessential amino acids
- Converting ammonia to urea
- Liver ammonia and carbon dioxide
- Dietary protein
27Preview of Protein Metabolism
28Preview of Protein Metabolism
29Preview of Protein Metabolism
- Excreting urea
- Liver releases urea into blood
- Kidneys filter urea out of blood
- Liver disease
- Kidney disease
- Protein intake and urea production
- Water consumption
30Preview of Protein Metabolism
31Protein Quality
- Two factors
- Digestibility
- Other foods consumed
- Animal vs. plant proteins
- Amino acid composition
- Essential amino acid consumption
- Nitrogen-containing amino groups
- Limiting amino acid
32Protein Quality
- Reference protein
- Preschool-age children
- High-quality proteins
- Animal proteins
- Plant proteins
- Complementary proteins
- Low-quality proteins combined to provide adequate
levels of essential amino acids
33Protein Regulations for Food Labels
- Quantity of protein in grams
- Percent Daily Value
- Not mandatory
- Protein claims
- Consumption by children under 4 years old
- Quality of protein
34Protein-Energy Malnutrition (PEM)
- Insufficient intake of protein, energy, or both
- Prevalent form of malnutrition worldwide
- Impact on children
- Poor growth
- Most common sign of malnutrition
- Impact on adults
- Conditions leading to PEM
35Protein-Energy Malnutrition (PEM)
- Marasmus
- Chronic PEM
- Children 6 to 18 months
- Poverty
- Little old people just skin and bones
- Impaired growth, wasting of muscles, impaired
brain development, lower body temperature - Digestion and absorption
36Protein-Energy Malnutrition (PEM)
- Kwashiorkor
- Acute PEM
- Children 18 months to 2 years
- Develops rapidly
- Aflatoxins
- Edema, fatty liver, inflammation, infections,
skin and hair changes, free-radical iron - Marasmus-Kwashiorkor mix
37Protein-Energy Malnutrition (PEM)
38Protein-Energy Malnutrition (PEM)
- Infections
- Degradation of antibodies
- Dysentery
- Heart failure and death
- Rehabilitation
- Rehydration and nutrition intervention
- Add protein slowly
39Health Effects of Protein
- High-protein diets
- Heart disease
- Animal-protein intake
- Homocysteine levels
- Arginine levels
- Cancer
- Protein-rich foods not protein content of diet
- Kidney disease
- Acceleration of kidney deterioration
40Health Effects of Protein
- High-protein diets
- Osteoporosis
- Calcium excretion increases
- Ideal ratio has not been determined
- Animal protein intake
- Weight control
- Satiety
41Recommended Intakes of Protein
- Need for dietary protein
- Source of essential amino acids
- Practical source of nitrogen
- 10 to 35 percent of daily energy intake
- RDA
- Adults 0.8 grams / kg of body weight / day
- Groups with higher recommended intakes
- Assumptions
42Recommended Intakes of Protein
- Protein in abundance
- Intake in U.S. and Canada
- Dietary sources
- Serving sizes
- Key diet principle moderation
43Protein and Amino Acid Supplements
- Protein powders
- Muscle work vs. protein supplements
- Athletic performance
- Whey protein
- Impact on kidneys
- Amino acid supplements
- Potential risks associated with intake
- Lysine tryptophan
44Highlight 6
45Nutritional Genomics
- New field
- Nutrigenomics
- Nutrients influence gene activity
- Nutrigenetics
- Genes influence activity of nutrients
- Human genome
46Nutritional Genomics
47A Genomics Primer
- DNA
- 46 chromosomes
- Nucleotide bases
- Gene expression
- Genetic information to protein synthesis
- Gene presence vs. gene expression
- Epigenetics
- DNA methylation
48A Genomics Primer
49Genetic Variation and Disease
- Genome variation
- About 0.1 percent
- Goal of nutritional genomics
- Customize recommendations that fit individual
needs - Single-gene disorders
- Phenylketonuria (PKU)
50Genetic Variation and Disease
- Multigene disorders
- Study expression and interaction of multiple
genes - Sensitive to environmental influences
- Example
- Heart disease
- Single nucleotide polymorphisms (SNPs)