Lecture 7 - Protein Flashcards
low muscle mass has been associated with ….
increased morbidity, poorer quality of life and higher mortality
Low muscle strength was shown to be a significant …
and independent predictor of mortality risk
structural functions of protein in the body
collagen / keratin for bone, skin, nails, tendons and ligaments
what are the transport functions of protein
hemoglobin (O2 and CO2)
cytochromes (ETC)
lipoproteins (lipids)
what are the immune functions of protein
antibodies (eliminates foreign pathogens)
what are the contraction functions of protein
actin / myosin
what are the metabolic functions of protein
enzymes and hormones
what is the amino acid structure
- carboxyl group
- amine group
- variable group
what is a dipeptide
composed of 2 amino acids that are joined by a chemical bond, known as a peptide bond
what is a polypeptide
longer chains of amino acids
what is the primary structure of a protein determined by
amino acid sequence
what is the secondary structure determined by
determined by the interactions between groups
what is the tertiary structure of protein determined by
determined by interactions between side chains
what is the protein digestion in the stomach
hydrochloric acid denatures the proteins and pepsin degrades proteins to large polypeptides and amino acids
what is the protein digestion in the pancreas
pancreatic enzymes include trypsin and chylotrypsin degrade polypeptides to oligopeptides and amino acids
what is the protein digestion in the small intestine (and are they transported across intestinal membrane)
aminopeptidase degrade oligopeptides to peptides and amino acids
amino acids and small peptides are transported across intestinal membrane. Peptides are hydrolysed in the cytosol and thus amino acids enter circulation
can we store amino acids in the body
no
the amino acids in the extracellular fluid and in the blood represent what
the amino acid pool
the liver plays a crucial role in regulating the composition of the
amino acid pool
muscle gain happens when
muscle protein synthesis is greater than muscle protein breakdown
muscle protein synthesis depends on what
post prandial rise in plasma essential amino acid concentrations
what is leucine sensed by and what does this promote
sestrin2, this promotes translocation of mTORC1 to the lysosome membrane where it becomes activated - this causes activation of downstream anabolic signalling pathways
what does muscle protein synthesis vary between
varies between different dietary protein sources
not all proteins are the same, what differs
amino acid profiles
what protein has been found to have fast protein synthesis rate
whey protein
what is protein absorption like compared to carbs and fats
slow
plant based foods have a lower … when compared with protein animal based foods
lower absorbability
why do plant based sources of protein have a lower absorbability
because of anti nutritional factors in plant based foods
why was there increase in protein synthesis from whey protein but not as much of an increase in from the same amount of wheat protein
not as much leucine, need more of the wheat protein to have the same effect
Ingesting what amount of whey protein (providing 2.2–2.7 g leucine) strongly increases muscle protein synthesis rates
20–25 g
how much wheat protein would you need to consume to get 2.7grams of leucine
45grams
what is the general rule of leucine content in animal proteins compared to plant proteins
(8-13%) compared to (6-8%)
what is the potential solution to low protein content in food
protein exraction
what is the potential solution to low protein and low in specific essential amino acid
protein fortification
what is the potential solution to low in specific essential amino acids
protein blends
what is the potential solution to overall low essential amino acid content
increase protein intake
how much protein do you need to maximise protein synthesis
current evidence suggest an intake of 0.3-0.4 per kg of body mass when consumed with food
a study found myofibrillar protein synthesis to remain elevated above rest for …
12 hours following a single bout of resistance exercise and protein
rates of protein synthesis are found to be highest with what intake of a moderate quantity of rapidly digested whey protein
intermediate intake (i.e every 3 hours)
how long is the anabolic window found to be elevated for
24-48 hours
why are whole eggs better for protein synthesis than egg whites
whole egg matrix is rich in high quality dietary protein, lipids, vitamins, and minerals compared to the egg white matrix
While dietary amino acids are the main precursors for protein synthesis, the non-protein components of the whole egg, which are largely contained in the yolk may have a role in
may have a role in various aspects of the regulation of muscle protein synthesis rates (MPS).
what is the limiting amino acid in soy
methionine
what are the limiting amino acids in corn
lysine, tryptophan
what are the limiting amino acids in legumes
tryptophan, methionine and cysteine
what is the limiting amino acid in rice
lysine
what is the limiting amino acid in wheat
lysine
what is the absorption rate of soy protein isolate
3.9g/hr
what is the absorption rate of casein isolate
6.1 g/hr
what is the absorption rate of whey isolate
8-10 g/hr
leucine is an amino acid that triggers what process
translocation of mammalian target rapamycin complex 1 (mTOR)
the amino acid pool is constantly being turned over, what % does this contribute to BMR
~20%
what are the branched chain amino acids
lsoleucine
leucine
valine
what has the highest leucine content
whey
what are the protein recommendations for sedentary (g/kg/d)
0.8 g/kg/d
what are the protein recommendations for recreational (g/kg/d)
0.8-1.0 g/kg/d
what are the protein recommendations for resistance athletes (steady state)
1.0-1.2 g/kg/d
what are the protein recommendations for moderate intensity endurance athletes (g/kg/d)
1.2 (g/kg/d)
what are the protein recommendations for resistance athletes (early training) (g/kg/d)
1.5-1.7 g/kg/d
what are the protein recommendations for elite male endurance athletes (g/kg/d)
1.6 g/kg/d
what are the protein recommendations for football, power sports (g/kg/d)
1.4 - 1.7 g/kg/d
how should athletes optimally stimulate protein synthesis
by consuming 20-30grams of protein at a serving over 3-4 feeding occasions per day
what are the essential amino acids
lsoleucine (BCAA)
leucine (BCAA)
lysine
methionine
phenylalanine
threonine
tryptophan
valine (BCAA)
what are the non essential amino acids
alanine
arginine
asparagine
aspartate
cysteine
glutamate
glutamine
glycine
histidine
proline
serine
tyrosine
what is the absorption rate of carbs
60-100g/hr
what is the absorption rate of fat
~14g/hr
what % of protein in egg whites, whole eggs, and chicken is absorbed
~ 85–95%
what % of protein in chickpeas, mung beans, and yellow peas is absorbed
~ 50–75%
is collagen a quality protein
no
