Lecture #5 Slides - Protein I Flashcards
1
Q
In ancient greek and roman times, athletes consumed meat-rich diets why?
A
because they believed that they would achieve the strength of the consumed animal
2
Q
the average 70 kg human contains __kg of protein
A
12
3
Q
Approximately __% of protein in the human body is contained within where?
A
40%; actin and myosin
4
Q
How much protein is synthesized by the body itself every day?
A
200-500 grams
5
Q
How many grams of protein are excreted per day?
A
10g
6
Q
Protein synthesis vs protein consumption over the lifetime?
A
10,000 kg synthesis vs 2,000 kg consumption
7
Q
Name some of our “working” proteins?
A
- enzymes
- antibodies
- transport vehicles
- hormones (neuro & -endocrine pumps)
- cellular pumps
- cell receptors
8
Q
What do our “working” proteins do?
A
- Carry O2
- Maintain fluid balance
- Contribute to acid/base balance
- Gluconeogenesis
- Immune function
- Energy yielding
9
Q
What are examples of “structural”proteins?
A
- tendons
- ligaments
- muscles
- scars
- core of bone and teeth
- hair filaments
- finger and toe nails
10
Q
How often are “structural” proteins being recycled?
A
some on the order of minutes and some on the order of years… it really depends
11
Q
40% of the total protein in the human body: structural proteins in the ____ and working proteins that act as?
A
myofibrils; enzymes, transporters within muscle cells (mitochondria & sarcoplasm)
12
Q
Muscle protein accounts for __-__% of the total protein turnover in our bodies.
A
25-35%
13
Q
Contractile proteins ___ and ___ are the most abundant proteins in the body. How much of muscle protein do they account for?
A
actin and myosin; 80-90%
14
Q
Do most Canadians get enough protein in their diet?
A
yes! rich or poor canadians get enough
15
Q
High protein diets are statistically what three things?
A
- high fat
- low fibre diets
- high disease rates
16
Q
How many amino acids are there?
A
20 - each with the same basic backbone
17
Q
What differentiates the amino acid?
A
the R group
18
Q
What three things does the R-group effect?
A
affect size, shape, electrical charge
19
Q
How many essential amino acids are there? What does the essential part mean?
A
9 essential acids; must get them in your diet
20
Q
How many of the 11 non essential AA are ‘conditionally essential’?
A
6 of 11; must be obtained in diet if endogenous synthesis cannot meet demands
21
Q
“a noncontractile muscles protein that connects adjacent sarcomeres”
A
titin protein
22
Q
How many different types of receptors are between the intestinal lumen and the intestinal epithelial cells? Can the AA use more than one?
A
7; yes, most can use > 1
23
Q
See “digestion and absorption of proteins” slide in Protein 1
A
big diagram
24
Q
Absorption of Proteins: AA, dipeptides and tripeptides are absorbed by _____ transport
A
active
25
Absorption of Proteins: flow is mostly with or against concentration gradients?
against
26
Absorption of Proteins: AA are co-transported with ___
sodium
27
The small intestine is very effective:
1
28
AA require __ because it is active transport
ATP
29
Not all AA can use all 7 channels, but all AA can use more than one channel. Because of this, why is supplementing a bad thing?
They can compete for channel usage - if you over supplement a certain AA, then it can block the channels that need to be used by other AA
30
If you have too many AA you have to remove them. How does this happen?
The nitrogen group (amine group) is removed
31
when the nitrogen group is removed, that is produced?
ammonia (toxic) and ketoacid
32
AA can ultimately be used to do what three things?
1. build proteins
2. synthesize other nitrogen-containing compounds such as vitamins,NT, and hormones
3. be converted to other AA
33
When nitrogen is removed, the remaining carbon skeleton (ketoacid) can be: (3 things)
1. burned as fuel (via TCA cycle)
2. converted to glucose and stored
3. converted to fat and stored
34
when nitrogen is removed and the remaining keto-acid is converted to glucose, what body part does this?
the liver! that is why too much protein can harm the liver
35
We do not have a large storage pool, so most AA are stored as what 4 things?
- body tissue
- hormones
- enzymes
- antibodies
36
_____ is when the amine group is removed, and a keto-acid is left. Where does this take place?
deamination; the liver
37
What happens to the nitrogen bi-product of deamination?
goes into urea and is excreted - this is a loss of AA
38
What happens to the carbon reside bi-product from deamination?
stored as fats or carbohydrates or is used as energy
39
Over eating protein can lead to increased deamination and therefore more glucose, why can this be bad?
insulin spikes!!!
40
What is the major contributor to lean body mass in human beings?
skeletal muscle
41
____ appears to increase the rate of deposition of muscle protein, much of this change can be attributed to what?
feeding; action of amino acids (without much influence of insulin)
42
T/F: all 20 amino acids are required to make proteins
T
43
What happens to the AA when protein anabolism is stimulated?
they are integrated into proteins - this is called MPS
44
What it it called when AA are integrated into proteins?
MPS
45
What three AA make up 40% of AA in the body?
Leucine
Isoleucine
Valine
46
Essential AAs are sometimes referred to as what?
BCAAs
47
leucine, isoleucine, and valine all appear to be strong ____sinals for what?
anabolic; muscle protein synthesis
48
Following consumption, blood concentrations of AA remain elevated for how long?
several hours (approx 2-3)
49
What is the magic number for protein consumption in a does? What happens if you go beyond?
20g; you shift into gluconeogenesis
50
What does chronically high insulin lead to?
type II diabetes
51
In the Bohe et al 2013 paper, what did they find happened at the 43.5mg/kg/h does of AA?
- unchanged from basal
| - MPS rose by 30%
52
In the Bohe et al 2013 paper, what did they find happened at the 87 mg/kg/h dose of AA?
- rose initially but after 30 min returned to basal
| - MPS rose by 50%
53
In the Bohe et al 2013 paper, what did they find happened at the 261 mg/kg/h dose of AA?
- rose 4-5 fold within 15 minutes
| - plateau at 3 times basal
54
When looking at the relationship between blood and intramuscular [AA], what did Bohe et al 2013 find happens in the first hour?
- extracellular EAA rose rapidly
- intracellular response was differential
- decreases due to MPS stimulated via exogenous AA
- decreases due to sensor on muscle membrane
55
When looking at the relationship between blood and intramuscular [AA], what did Bohe et al 2013 find happens in hours 1-3.5?
- extracellular (plasma) EAA inc +41 to 82%
- Associated with MPS rate increases of 30 to 57%
- All muscle proteins (myofibrillar, sarcoplasmic, mitochondrial)
56
For MPS to occur, what two things do you need?
- exercise
| - the proper amount of AA (20g)
57
Only modest amounts of dietary AA needed to achieve max stimulation of the muscle anabolic processes - the average adult is 55-75 kg x ____ mg/kg/h x 2 hr OR approximately _-_ g of protein (in 4ish hours)
0.260; 30-40 grams of protein
58
What are the daily recommendations of protein by the FAO/WHO/UNU?
0.8g/kg/day OR 1.2g/kg/day for athletes
59
less muscle mass is aka?
sarcopenia
60
```
Protein Requirements:
Childhood (0-6mo) =
Late childhood (6mo-13yr) =
Young Adulthood (14-18) =
Adults (19+) =
Older adults (65+) =
Throughout life, what are these requirements based on?
```
1.5 g/kg/day
1.0 g/kg/day
0.9 g/kg/day
0.8 g/kg/day
1.2 g/kg/day
The lean body weight of an individual
61
What is the purpose of DRIs for Protein?
to promote nitrogen balance and to make sure you have enough but not too much
62
How would you calculate DRI for protein for a 70kg 35 year old individual?
70 x 0.8 = 56 g per day
63
During pregnancy, how should the DRI for protein change?
inc by 25g/day (or approx 15% of energy intake)
64
The DRI for women is __ g but the average intake is __ g. The DRI for men is ___ g but the average intake is ___g.
46;72
| 56; 109
65
People that do advocate for inc protein consumption in athletes say that anaerobic or RT athletes should consume __-__ g/kg/day and ultra-endurance athletes should have up to __ g/kg/day
1. 2-1.4 (1.8?)
| 2. 5
66
What four groups of athletes are potentially at risk from protein and energy deficiency?
1. female runners
2. male wrestlers
3. male and female gymnasts
4. female dancers
67
Protein turnover within muscle is the sum of what two processes?
MPS and muscle protein breakdown (MPB)
68
When MPS > MPB this is called ______. When MPB > MPS this is called _____.
hypertrophy; atrophy
69
Post exercise _____ suppresses rise in MPB
hyperaminoacidemia
70
T/F: RT in a fasted state increases MPB
True
71
MPS is a saturable process; for young people it is __-__g or approx __-__g of EAAs (regardless of exercise or not) and for older adults it is __g post exercise and __g at rest
20-25; 8.5-10
| 40;20
72
When ___ is added to other EAA, it will increase MPS
leucine
73
Whey, soy, casein. Put in order for digestibility and stimulus of MPS.
Digestibility: Whey > Soy > Casein
Stimulus of MPS: Whey > Casein > Soy
74
In what 4 scenarios are AA wasted?
1. Energy from other sources is lacking
2. Protein is overabundant (from diet)
3. A specific AA is oversupplied (supplementation)
4. Only low quality protein present in diet (too few EAAs, limiting AAs, and limited protein synthesis rate)
75
When we have an excess of AAs or protein - the ___ groups are cleaved, this is called _____
amine; deamination
76
When the amine group is cleaved, what happens to the remaining keto-acid?
it is burned as fuel (in the TCA cycle) or converted to fat or glucose
77
Remaining nitrogen by-products can be changed to free ____ quite easily, but it is very toxic in the blood
ammonia
78
What are the 6 AA that are commonly oxidized in meaningful amounts?
```
Leucine
Isoleucine
Valine
Asparagine
Aspartate
Glutamine
```
79
PROBLEM and SOLUTION to dealing with the nitrogen?
PROB: how to get toxic NH3 from body tissues to the liver in a safe manner?
SOLU: transamination
80
"the process of transferring the amino group to a keto-acid molecule, resulting in the formation of another AA"
transamination
81
Where is transamination usually done?
in the liver
82
How is glutamine converted to glutamate?
Glutamine is carried to the liver where it releases the nitrogen (becoming glutamate) as ammonia which goes into the urea and the kidneys excrete it!
83
____ proteins tend to have rapid turnover: minutes, hours, or days
regulatory/signaling
84
_____ proteins have a slower turnover: days, weeks, months, years
structural
85
Name some regulatory/signaling proteins and structural proteins
Reg/Sig: enzymes, hormones
| Structural: collagen, actin, myosin
86
In healthy humans, what should be the overall synthesis and degradation ration for nitrogen?
nitrogen in = nitrogen out
87
During nitrogen balance, protein ___ > protein _____
turnover, intake
88
Where do the majority of AA come from?
the gut, kidneys, and liver
89
A balanced diet of __-__% of calories from proteins will, in most cases, provide you with adequate AA, even for those who exercise strenuously.
12-15%
