Kin146 – final notes
Proteins are the second most abundant component of plants and animals
- Found in meat, fish, milk, dried beans, peanuts, nuts, seeds, and some vegetables
Proteins are made of amino acids
- 20 total but 9 are essential
o Essential amino acids; can’t be synthesized by body
Tyrosine is made up of phenylalanine
Cysteine is made up of methionine
- Protein synthesis occurs from DNA, mRNA, and tRNA
o AA’s are taken up by rRNA and turned on by hor emones and signalling
molecules
Structure: 20200 proteins can be made
- Primary: dipeptide
Protein denaturation;
- Occurs due to pH, heat, alcohol, oxidation, or mechanical agitation
o Eggs (ovatransferrin, ovalbumin denature at higher heat to become firm and make
“bubbles” due to mechanical agitation)
Protein functions
- Mechanical;
o Collagen; provides structure to tissues
o Biomolecular motors; harness energy for body
- Enzymes;
o Catalyze chemical reactions
- Hormones;
o Insulin, TSH, leptin
- Immune function
o Antibodies and blood proteins neutralize antigen actions
- Fluid balance
o Albumin and globulins in the blood are to big to leave CV system common
sign of protein malnutrition
- Acid-base balance
o Normal pH of 7.4 blood proteins can bind to alkaline atoms/molecules to
buffer an acidic pH
- Transport functions
o Lipoproteins are used in transport
- Energy
, o Oxidative deamination, formation of glucose, converting excess protein to fatty
acids
Protein digestion:
- Begins in stomach; protein is denatured by HCl (pH: 0.8) pepsin breaks down proteins
further to be digested (pH: 2.5)
- Small intestine; amino acids and dipeptides enter
o Proteases catalyze large to small peptides
o Trypsin/chymotrypsin (pancreas); catalyze large to small peptides
o Peptidases (intestinal wall); catalyzes tri-, and di-peptides into amino acids
- Duodenum and jejunum; facilitated diffusion via membrane proteins or active transport
brings in Na+ and amino acids
o Downside is too many of one AA will cause saturation and restrict essential AA
absorption
- AA’s are stored as protein or metabolized
o AA supplements not needed, just add a bit of energy
Can interfere w/absorption
Excess AA excess protein that enters urea cycle (dehydration) or is
converted to fat
Recommended RDA for 15-18-year-old females is 0.8 grams/kg of body mass, while 1.2-1.8g/kg
of body mass for stretch athletes (1.2-1.5g/kg of body mass for endurance athletes)
- Increased protein consumption is needed for pregnancy, illness, surgery, or burns
o Strength athletes: protein synthesis
o Endurance athletes: energy substrate in long distance
High quality protein; provides all essential AA’s, provides enough amino acids to serve as
nitrogen sources to synthesize non-essential amino acids, and are easy to digest and absorb
- Animal and plant-based foods
o Plant-based proteins are considered complementary (some are low-quality)
Combining plant-based foods to achieve adequate amino acid digestion
and absorption
o Combine grains and legumes OR legumes and nuts/seeds
Soybean-based foods
- Low saturated fat and no cholesterol
o Genistein (CCG and O)
Inhibits cancer cell growth and prevents oxidation (plaque forming)
o Phytoestrogens (CVD and osteoporosis in women)
Proteins are the second most abundant component of plants and animals
- Found in meat, fish, milk, dried beans, peanuts, nuts, seeds, and some vegetables
Proteins are made of amino acids
- 20 total but 9 are essential
o Essential amino acids; can’t be synthesized by body
Tyrosine is made up of phenylalanine
Cysteine is made up of methionine
- Protein synthesis occurs from DNA, mRNA, and tRNA
o AA’s are taken up by rRNA and turned on by hor emones and signalling
molecules
Structure: 20200 proteins can be made
- Primary: dipeptide
Protein denaturation;
- Occurs due to pH, heat, alcohol, oxidation, or mechanical agitation
o Eggs (ovatransferrin, ovalbumin denature at higher heat to become firm and make
“bubbles” due to mechanical agitation)
Protein functions
- Mechanical;
o Collagen; provides structure to tissues
o Biomolecular motors; harness energy for body
- Enzymes;
o Catalyze chemical reactions
- Hormones;
o Insulin, TSH, leptin
- Immune function
o Antibodies and blood proteins neutralize antigen actions
- Fluid balance
o Albumin and globulins in the blood are to big to leave CV system common
sign of protein malnutrition
- Acid-base balance
o Normal pH of 7.4 blood proteins can bind to alkaline atoms/molecules to
buffer an acidic pH
- Transport functions
o Lipoproteins are used in transport
- Energy
, o Oxidative deamination, formation of glucose, converting excess protein to fatty
acids
Protein digestion:
- Begins in stomach; protein is denatured by HCl (pH: 0.8) pepsin breaks down proteins
further to be digested (pH: 2.5)
- Small intestine; amino acids and dipeptides enter
o Proteases catalyze large to small peptides
o Trypsin/chymotrypsin (pancreas); catalyze large to small peptides
o Peptidases (intestinal wall); catalyzes tri-, and di-peptides into amino acids
- Duodenum and jejunum; facilitated diffusion via membrane proteins or active transport
brings in Na+ and amino acids
o Downside is too many of one AA will cause saturation and restrict essential AA
absorption
- AA’s are stored as protein or metabolized
o AA supplements not needed, just add a bit of energy
Can interfere w/absorption
Excess AA excess protein that enters urea cycle (dehydration) or is
converted to fat
Recommended RDA for 15-18-year-old females is 0.8 grams/kg of body mass, while 1.2-1.8g/kg
of body mass for stretch athletes (1.2-1.5g/kg of body mass for endurance athletes)
- Increased protein consumption is needed for pregnancy, illness, surgery, or burns
o Strength athletes: protein synthesis
o Endurance athletes: energy substrate in long distance
High quality protein; provides all essential AA’s, provides enough amino acids to serve as
nitrogen sources to synthesize non-essential amino acids, and are easy to digest and absorb
- Animal and plant-based foods
o Plant-based proteins are considered complementary (some are low-quality)
Combining plant-based foods to achieve adequate amino acid digestion
and absorption
o Combine grains and legumes OR legumes and nuts/seeds
Soybean-based foods
- Low saturated fat and no cholesterol
o Genistein (CCG and O)
Inhibits cancer cell growth and prevents oxidation (plaque forming)
o Phytoestrogens (CVD and osteoporosis in women)
