-
Protein Denaturation
• Causes the protein to change shape or conformation.
• The protein and the amino acids are still intact.
• Can be caused by heat, alkali or acid treatments, or metals.
• Is required before the protein can be digested.
-
Protein Digestion
• The protein strand is broken and the amino acids are released.
• Occurs by the protease enzymes secreted by the pancreas and GI mucosal cells.
• Amino acids are absorbed,transported to cells and then used to build proteins.
-
Protein Synthesis
We eat protein, denature &digest the protein, absorb &transport the amino acids to the cells, then within each cell,protein is made (synthesized)according to the DNA.
-
Protein is synthesized in a
process of converting DNA to RNA and then protein
-
The Gene Encodes Proteins:
The human genome is a complete set of
genetic material organized into 46 chromosomes, located within the nucleus.
-
The Gene Encodes Proteins:
A chromosome is made of
DNA and associated proteins.
-
The Gene Encodes Proteins:
The double helical structure of a DNA molecule is made up of
two long chains of nucleotides. Each nucleotide is composed of a phosphate group, a five-carbon sugar, and a base.
-
The Gene Encodes Proteins:
The sequence of nucleotide bases (C, G, A, T) determines the
amino acid sequence of proteins. These bases are connected by hydrogen bonding to form base pairs - adenine (A) with thymine (T), and guanine (G) with cytosine (C)
-
The Gene Encodes Proteins:
A gene is a segment of
DNA that includes the information needed to synthesize one or more proteins.
-
Protein Character is determined by:
– How the 20 amino acids are combined together (the sequence).
– The polypeptide strand folding & interacting.
-
Types of Protein:
Fibrous
• Uniform in structure.
• Either exclusively helical or sheet formation.
• Examples are the proteins found in hair, muscle fibers &finger nails.
-
Types of Protein:
Globular
• Have variation in structure.
• Are part helical, part sheet,part random, or completely random.
• Examples of globular proteins include blood,mucous, milk protein and egg white.
-
Protein Functions
1. Growth & tissue maintenance (replace, repair &possibly add LBM).
2. Enzymes (catalysts).
3. Antibodies, complement proteins, circulating components of immunity.
4. Fluid & electrolyte balance (free proteins).
5. Acid - base balance (H donors & acceptors).
6. Energy (4 Cals/gm, requires N removal).
7. Protein hormones like insulin & glucagon, secretin & cholecystokinin.
8. Transportation of nutrients (lipoproteins).
-
Adult Protein Need (DRI & AMDR)Sample Calculations
• Eric weighs 90 Kg and ate 88 g of protein and 3000 Calories in one day.
- • What is his DRI for protein?
- – 90 Kg x 0.8 gm/Kg = 72 gm protein
- • What % of his DRI for protein did he consume?
- – 88 gm ÷ 72 gm x 100 = 122%
- • What % of Calories in his diet came from protein?
- – 88 g protein x 4 Cal/gm = 352 Cals from protein
- – 352 Cals ÷ 3000 Cals x 100 = 11.7%
-
Protein deficiency is called
Kwashiorkor. The individual has peripheral edema and may not look undernourished.
-
Protein-Energy deficiency is called
Marasmus. The individual looks undernourished (skin &bones, starvation).
-
In the U.S. individuals who are on starvation diets, poor,abused, or in hypermetabolic states can experience
Kwashiorkor or Marasmus.
-
Protein Excess is most common in
athletes and fad dieters.
-
Protein Excess:
Increases risk of
- – Dehydration.
- – Liver & spleen enlargement.
- – Accelerated kidney aging.
- – Metabolic acidosis (with low carbohydrate intake)
- – Vitamin B6 deficiency, Ca & Zn loss.
- – Heart disease & cancer.
-
What it takes to gain muscle:
One pound muscle is:
75% water, 20%protein, 5% other material like fat,glycogen, minerals, enzymes.
-
One pound muscle equals
105 grams protein
-
To gain one pound muscle in 2 weeks an athlete would need an extra
7-8 g protein/day intake.
– 1 oz meat, 1 cup milk, 3 slices bread.
|
|
