Protein & Amino Acids

Components of Protein Amino acid chains (up to 300 AA) Amino acid consists of: 1. Amine group (NH3+) 2. Hydrogen 3. Carboxyl group (COO-) 4. R side chain

Components of Protein Peptide bonds: Amine and carboxyl groups Dipeptide Tripeptide Polypeptide Protein

Components of Protein Twenty different amino acids Essential (9) & nonessential (11) Complete vs. noncomplete protein Animal vs. vegetable Complementary proteins Beans & Rice Beans & Corn or Wheat Peanut butter & Bread

Essential Amino Acids Leucine* Isoleucine* Valine* Histidine Lysine Methionine Phenylalanine Threonine Tryptophan *Branched Chain Amino Acids

Protein Metabolism Four components: 1. Protein synthesis 2. Protein degradation 3. Amino acid oxidation 4. Gluconeogenesis

Protein Synthesis Dietary protein  digestion  amino acids in blood Cells use amino acids

Protein Degradation Cells break down Protein not stored Removal of catabolized PRO needed Blood  liver (deamination) Excreted as urea Converted to fat or CHO Oxidized as energy

TCA Intermediates Pyruvate

Gluconeogenesis Glucogenic amino acids Glucose-alanine cycle

Characteristics of Skeletal Muscle Comprises 40-45% of body weight Contains 50% of total body protein Composed of water & protein in 4:1 ratio Body protein turns over at 3-4 g/kg/day Skeletal muscle turns over at 1 g/kg/day Skeletal muscle is 25% of total turnover

Exercise and PRO Req. PRO oxidation during exercise Endurance Resistance PRO breakdown and synthesis during resistance training

PRO Oxidation During Exercise Endurance training  Inc. muscle mitochondrial protein enzymes (leucine oxidation) Typically 5%-15% of resting metabolism Prolonged endurance ~ 10% max Depletion of glycogen Protein not from contractile protein Recommendation is g/kg

PRO and Strength Training Resistance training  PRO breakdown Resistance training does not increase protein oxidation significantly Next hrs.  protein anabolism Also needed for recovery/repair Eccentric Recommendation is g/kg

Protein and Muscle Anabolism 1 lb muscle contains 100 g protein (22%) Reasonable muscle gain is 1 lb/week Additional 14 g per day protein or 0.14 g per kg for 100 kg individual kcal/day to support additional tissue growth

How much is g of PRO? 6 oz. Chicken breast = 48 g 1 cup skim milk = 8 g ½ cup peanuts = 18 g 2 oz. Cheddar cheese = 14 g Grand total = 88 g