Protein & Creatine

Question 1

Functions of Proteins

Answer 1

• Structural Components in cell
• Contractile proteins: actin, myosin
• Enzymes
• Transport molecules: hemoglobin, myoglobin, albumin
• Hormones: insulin

Question 2

Urea

Answer 2

• Major end product of nitrogen metabolism
• Ammonia from oxidative deamination must be removed
• Urea cycle converts ammonia to urea

Question 3

Recommended Dietary Allowance

Answer 3

-Daily dietary intake level considered sufficient to meet requirements of 97-98% of healthy people

Question 4

RDA of Protein

Answer 4

0. 8g/kg body weight
1. 36g/lb body weight
   - increases to 0.5-0.8g/lb if training
   - too much protein takes away from the more efficient CHO energy usage
   - Can generally be met through diet alone

Question 5

Excess protein ingestion effects

Answer 5

• excess acid load
• increased urinary loss of calcium
• insufficient carb intake
• higher fluid needs

Question 6

Lab Assessment of Protein Status

Answer 6

• Serum albumin: transport and osmolarity
  
  • poor indicator of early protein depletion/repletion
• Transferrin: transport for iron
  
  • Index of protein status change
• Prealbumin: bind retinol binding protein
  
  • sensitive indicator of protein status

Question 7

Protein Signaling Molecules

Answer 7

• Nutrient Availability: modulates protein response to exercise
• Muscle protein turnover: regulated by hormones, nutrition, and metabolism
  
  • Insulin and aa supply crucial
• Exercise: increases muscle building and decreases muscle breakdown

Question 8

Fast vs. Slow Proteins

Answer 8

• Fast increase blood aa rapidly
  
  • stim protein synth and oxidation
  • Whey protein
• Slow promote post-prandial protein deposition
  
  • inhibit breakdown
  • Casein protein

Question 9

Leucine

Answer 9

• Potent independent stimulator of muscle protein synthesis (MPS)
• Adding it to good protein mix does NOT enhance MPS
  
  • aa transport is rate limiting step in MPS
• Leu to EAA supplement elicits greater MPS response during recovery than EAA alone

Question 10

Beta Hydroxy beta Methylbuterate (HMB)

Answer 10

• May be signal to activate protein synth or inhibit degradation
• Purported to decrease muscle breakdown and damage
• No receptors yet identified

Question 11

Beta alanine/Carnosine

Answer 11

• Carnosine: dipeptide of beta alanine and histadine
• High in skeletal muscle
• Protects agains free radicals and lipid peroxidation
• Membrane-protecting activity & proton buffering capacity

Question 12

Synthesis of Creatine

Answer 12

• 3 amino acids
• S-adenosyl methionine (SAMe), GLY, ARG
• GLY & ARG combo to form guanidinoacetate
• guanidinoacetate methylated w/ SAMe to form creatine
• Metabolic burden on amino acid metabolism

Question 13

Creatine Kinase

Answer 13

• Reversibly catalyzes transfer of phosphate b/t ATP and creatine phosphate
• Two forms: Muscle (M) and brain (B)
• Dimers: MM is in skeletal muscle
• Clinical marker of MI, muscular dystrophy, and severe exertion

Question 14

Creatine Kinase Function

Answer 14

• Temporal buffer of ATP during high energy demand or O2 insufficiency
• Controls oxidative phosphorylation
• Buffer of protons

Question 15

Degradation of Creatine to Creatinine

Answer 15

• Spontaneous cyclization occurs
  
  • relatively constant rate
• Creatinine increases w/:
  
  • muscle catabolism
  • muscular dystrophy
  • High creatine intake

Question 16

Creatine & Performance

Answer 16

• May enhance explosive strength/ short high intensity activities in combo w/ proper training
• Does NOT improve endurance performance
• Responders v. Non-responders
  
  • not everyone sees performance or muscle gain improvements
• Creatine monohydrate believed to be safe
  
  • shown to increase anterior compartment pressure in lower leg
• Safe effective dose: 3g/day
• Cycle 28d on 28d off b/c takes greater than 28d to return to original levels