7. integrative metabolism protein Flashcards
why protein requirement is small
high turnover between synthesis, degradation and conversion
- most of breakdown is recycled
fate of protein
- formation of glutamate and alanine
- forms alpha-ketoglutarate for krebs cycle - urea production
- excreted, increases with exercise, escpecially carb depleted - branched chained amino acids
- lecuine, isoleucine, valine
- increase in muscle in proportion to aerobic exercise intensity
central fatigue hypothesis
increase BCAA plasma concentration
reduce Trp uptake
less serotonin production
– less rapid fatigue
little evidence supporting this theory
affect of insulin on protein metabolism
increase synthesis
decrease degredation
CHO ingestion with amino acids
raises insulin levels
leucine very effective at increasing insulin levels
feature of whey protein
high in leucine
- large insulin increase
Aerboic exercise and protein synthesis, degredation and oxidation
synthesis
- decreased during prolonged aerobic exercise
- increased during recovery from prolonged exercise
degredation
- increased BUT not contractile protein (actin/myosin)
oxidation
- 2-6% total energy provision
resistance exercise with protein metabolism
stimulates synthesis and breakdown
- increased turnover 24 - 48 hrs post exercise
- if not enough food, degredation exceeds synthesis
- eat more protein and AAs
type of amino that promote protein synthesis
essential amino acids
- non essential no benefit
- leucine largest contributor
whey vs casein protein
whey
- quick transient increase in protein synthesis
- higher leucine in whey
- larger insulin
- rapid gastric emptying (AA in blood)
casein
- prolonged increase blood AA and net positive protein balance
- no difference in protein synthesis
- measured by nitrogen balance and Phe uptake
- whey maybe better b/c of larger insulin increase
addition of carb to amino acids
no benefit
- insulin increase more but no change in muscle protein synthesis (MPS)
aminos with greatest effect on insulin secretion
leu, phe, and arg
