Amino Acid Metabolism Flashcards
1
Q
Metabolism (carbs, lipicds, proteins)
FAD > FADH2
NAD+ > NADH + H+
A
CO2 + H2O + ATP
2
Q
Metabolism energy of proteins
A
dietary proteins
tissue proteins
3
Q
amino acids metabolism depends on what?
A
depends on the energy requirements of the cell
4
Q
amino acid degradation occurs under 3 circumstances depends on what body needs
A
we break down amino acids”
- protein turnover- break down our protein depends on diet
- protein rich diet- to much in body we break down what we dont use in body
- starvation, uncontrolled diabetes mellitus- dont have it so we use it as a fuel
5
Q
amino acid supply:
where are amino acids stored?
A
not stored in the body
6
Q
amino acid supply:
amino acids are not stored in the body:
A
dietary
synthesized
protein degradation
7
Q
amino acid supply:
Excess amino acids are catabolized
A
Step 1: removal of amino group (nitrogen)
Step 2: carbon skeleton
8
Q
what is the amino acid pool supplied by?
A
supplied by breakdown of endogenous protein dietary protein and synthesis of non essential AA
9
Q
amino acid pool:
Free amino acids:
A
cells
blood
extrzcellular fluid
10
Q
what is more abundant in the body proteins or free amino acids?
A
proteins are more abundant then Free Amino acids
11
Q
What is the fate of amino acids?
A
Low energy charge
low glucose
high energy charge and lots of glucose
12
Q
fates of amino acids and low energy charge
A
the amino acid is oxidized to recreate ATP
13
Q
fates of amino acids and low glucose
A
the amino acids id sent to the liver to turn into glucose
14
Q
fates of amino acids and high emergy charge and lots of glucose
A
the amino acid is sent to the liver and turned into fat
15
Q
what can amino acids also be used to synthesize?
A
amino acids may also be used to synthesize protein or nitrogen containing compounds
16
Q
Oxidation of amino acids means what?
A
means burning them in the aerobic system (krebs cycle and ETS) to get ATP
17
Q
What oxidaizes most of the 20 amino acids in protein
A
the liver does
18
Q
what can only oxidize significantly six?
A
muscle
19
Q
When are amino acids oxidized?
A
when the cells’ energy charge is LOW
20
Q
amino acid catabolism (alpha amino acids)
A
amino group - urea carbon skeleton (a keto acid) - ATP + CO2 + H2O - glucose -fatty acids
21
Q
amino acid catabolism (alpha amino acids)
A
amino group - urea carbon skeleton (a keto acid) - ATP + CO2 + H2O - glucose -fatty acids
22
Q
what is the primary site for uptake of most amino acids following a meal (50-60%)?
A
the liver
23
Q
what are 20% used for? and where do they stay and released?
A
20% for synthesis of protein; most stay in the liver while the rest are released into the plasma
24
Q
what are 20% used for? and where do they stay and released?
A
20% for synthesis of protein; most stay in the liver while the rest are released into the plasma
25
what is the 1st step in liver amicno acid metabolism?
| where is it transferred?
step 1:
remove amino group: transmination (aminotransferase)
amino group transferred to a-ketoglutarate
26
glutamate and liver amino acid metabolism
amino group donor- bissynthetic pathways
| excretion pathway of nitrogen
27
along with the liver what is also used in transamination?
peripheral tissues
28
where do most amino acids transfer their a-amino group to
to a a-ketoglutarate (amino group acceptor)
29
what are the results after the transfer of the a-amino group to the a-ketoglutarate?
results in glutamate and a an a-keto acid
30
what is the required conezyme for the transamination to happen?
pyridoxal phosphate (derivative of vitamin B6)
31
transamination:
| amino acid to a
ketoacid uses aminotransferase
32
transmination:
| a-ketoglutarate to
glutamate uses aminotransferases
33
alpha ketoacid:
a-amino acid to a ?
where is the amino group located here?
what is the carbonyl group associated with?
to a a-keto acid
amino group is on the alpha carbon
carbonyl group associated with the alpha carbon
34
what is left when the amino group is removed from an amino acid?
a-ketoacid is what is left
35
where is usually the amino group transferred to?
normally transferred to another a-ketoacid
36
where do ketoacids usually enter into metabolic pathways
krebs, gluconeogenesis, fat synthesis
37
what happens to an alpha keto acid depends upon what?
```
energy charge
horomones (glucagon/insulin)
respiratory quotient
glucose concentraion
tissue (liver vereus muscle)
```
38
what does every amino acid contain
an amino grouo (NH3)
39
what removes this amino group
amino acid catabolism removes this
40
what removes this amino group
amino acid catabolism removes this
41
where are most amino acids metabolized
in the lier
42
ammonia (NH3)
biosynthetic pathways
| excreted
43
ammonia from extrahepatic tissues are transport where and then?
transport to liver (glutamate, alanine)
| and excreted
44
what are the 4 amino acids in nitrogen metabolism?
glutamate
glutamine
alanine
aspartate
45
where can these amino acids in nitrogen ny easily converted to?
to krebs intermediates
46
glutamate to
a-ketoglutarate
47
glutamine to
a-ketoglutarate
48
alanine to
pyruvate
49
aspartate to
oxaloacetate
50
glutamate and a-ketoglutarate:
glutamine to glutamate by reduction of one (NH3)
| glutamate to a-ketoglutarate (a ketoacid) by lose of (NH3 and gain of oxygen)
51
alanine and pyruvate:
alanine (AA) to pyruvate (a ketoacid)
52
aspartate and oxaloacetate:
Asparagine to asparate by reduction of one (NH3)
| aspartate to oxaloacetate (a ketoacid) by lose of (NH3 and gain of oxygen)
53
glutamate and gluatmine collect?
collect amino acids
54
glutamate and gluatmine location? and transfer BLANK to BLANK?
liver;
| amino acids tranafer their amino group to a-ketoglutarate to form glutamate
55
where does glutamate enters to release amino group and then forms NH4+
enters mitochondria
56
glutamate and gluatmine and extrahepatice tissues
ammonia generated in extrahepatic tissues is converted to glutamine
transported to the liver
both make up the highest concentration of amino acids in the liver
57
glutamate and gluatmine and extrahepatice tissues
ammonia generated in extrahepatic tissues is converted to glutamine
transported to the liver
both make up the highest concentration of amino acids in the liver
58
amino group have been collected where as ? is transported where from? amino groups are removed by?
collected in the liver as glutamate; glutamate is tranported to mitochondria from cytosol; amino groups removed by oxidative deamination
59
what is oxidative deamination? and provides what? for what cycle?
removal of amino groups as free ammonia; of glutamate in the liver provides amino group for the urea cycle
60
glutamate to what by what?
glutamate to glutomine + NH4+ by:
| glutamatedehydrogenase (NAD+ > NADH) a-ketoglutarate
61
numerous transaminases are present to transfer the nitrogen to another molecule which will end up bringing it to the liver for deamination
skeletal muscle
62
glutamate to?
alpha KG
63
pyruvate to?
alanine
64
what is glutamate a transporter of?
transporter of ammonia
65
what is glutamate a transporter of?
transporter of ammonia
66
ammonia
is toxic
67
ammonia is converted to
a nontoxic compound to transport to the liver and kidneys
68
free ammonia is combined to?
glutamate from glutamine
69
glutamate + ATP >?
| by?
Glutamine + ADP Pi
by addition of NH3+
by glutamine synthetase
70
glutamine is a source of?
nitrogen
71
what maybe the donors of nitrogen to make glutamine in skeletal muscle?
```
LIV GAA
Glutamate
Aspartate
Leucine
Isoleucine
Valine
Asparagine
```
72
Muscle is responsible for giving other tissues nitrogen which makes it a? and builds 2 things?
makes it a nitrogen donor
builds amino acids
builds nitrogenous bases and nucleotides (new cells)
73
How is muscle able to be a nitrogen donor?
muscle does this by taking in certain amino acids, stealing their nitrogen and creating glutamine (2 nitrogen atoms) for export
74
LIV GAA to
| glutamate to
ketoacid
| glutamine
75
LIV GAA to
| glutamate to
ketoacid
| glutamine
76
what is aspartate also used for transporting?
transports malate-aspartate shuttle
77
where is aspartate formed?
formed in mitochodria: amino group transferred from glutamate to oxaloacetate to form as
78
where is aspartate formed? By?
formed in mitochodria: amino group transferred from glutamate to oxaloacetate to form aspartate
79
AST
aspartate aminotransferase AKA glutamate oxoloacetate transminase (GOT)
80
Aspartate is sent to ? to donate? for what cycle
sent to cytosol to donate nitrgoen for the urea cycle
81
glutamate + oxaloacetate>
a-ketoglutarate + aspartate
82
glucose- alanine cycle: maintains bloodg glucose through?
GNG
83
alanine may provide 5% of energy during?
exercise
84
where do the carbons in alanine come from?
came from muscle glycogen
85
where do the carbons in alanine come from?
came from muscle glycogen
86
glutamine-glutamate cycle:
| muscle imports?
imports glutamate
87
what does muscle turn glutamate into? by?
into glutamine;
by glutamine synthetase adds nitrogen to glutamate
NH3 comes primarly from BCAAS
88
glutamine then goes to where that need?
goes to cells that need nitrogen; Gut and immune cells
89
glutamine then turns back into? by?
back into glutamate
| glutaminase hydrolyzes glutamine into glutamate
90
where does glutamate then go?
goes back to the muscle
91
what maybe the donors of nitrogen to make glutamine in skeletal muscle?
```
LIV (branch chain amino acids) GAA
Glutamate
Aspartate
Leucine
Isoleucine
Valine
Asparagine
```
92
where does glutamate then go?
goes back to the muscle
93
skeletal muscle is onyl able to significantly oxidize what 6 amino acids?
```
LIV (branch chain amino acids) GAA
Glutamate
Aspartate
Leucine
Isoleucine
Valine
Asparagine
```
94
skeletl muscle and alanine (3)
contracting muscle
amino group transferred to a-ketoglutarate to form glutamate
glutamate gives amino group to pyruvate(making alanine)
95
contracting muscle
produces pyruvate and lactate from fast (anerobic) glycolysis
protein breakdown produces ammonia
96
glutamate gives amino group to pyruvate
ALT (alanine aminotransferase)
| glucose- alanice cycle
97
ALT muslce
- AKA glutamate- pyruvate transferase GPT
- pyruvate +glutamate> alanine + a-ketoglutarate
- exercising muscle produces lots of pyruvate and pushes the reaction toward alanine
98
ALT liver
- AKA glutamate- pyruvate transferase GPT
- alanine + a-ketoglutarate> pyruvate +glutamate
- lots of alanine arriving from muscle pushes the reaction toward pyruvate
- pyruvate is cleared by pyruvate carboxylase in GNG
99
glucose -alanine cylce:
| amino group trasnferred?
from glutamate to pyruvate
100
alanine transported to?
the liver and is converted back to pyruvate for GNG
101
Glucose is transported back to?
muscle
102
What is ammonia in the liver converted to?
Converted to urea (urea cycle)
103
Nitrogen that is not being used to synthesize amino acids or nitrogen containing products need to be excreted
Nitrogen excretion
104
Can nitrogen be store in the body?
No so it is sent to the liver to remove the amino groups (transmission oxidative deamination) and then excreted as urea
105
What's the components of nitrogen exodus?
Urea 86%
creatinine 5%
NH4+ 3%
Other 6%
106
Why does nitrogen go to the liver?
Excess protein eating (liver gets rid of excess nitrogen)
| Gluconeogenesis (exercise starvation not eating carbs)
107
What happens in the liver?
Transamination
Oxidative deamination
Carbomoyl phosphatase
Urea cycle
108
What are unique abilities of the liver?
Urea cycle: liver has ability to deal with ammonia (make urea)
Gluconeogenesis: liver can turn alpha ketoacids into glucose
109
How is NH3+ transported to the liver?
Glutamine (glutamate + ammonia= glutamine)
Enzymes glutamine synthetase
Not exclusive to muscle
Alanine
110
What are two entry points to the urea cycle? (Liver)
GDH:
Deamination glutamate
Glutamate + NAD+ > a-Ketoglutarate + NH3 + NADH
AST:
Aka GOT
transfers amino groups from glutamate to oxaloacetate
Forms aspartame (source of nitrogen)
Glutamate + oxaloacetate > a- Ketoglutarate + aspartame
111
What is carbamoyl phosphatase?
Enzyme in the liver which catalyzes in the mitochondria matrix
Goes to carbamoyl phosphate
112
Where is urea transported to to be excreted?
To the kidneys
113
Is all ammonia excreted through the kidneys?
No some diffuses back into and sent to GI and excreted through the feces
114
How many molecules of nitrogen are in urea?
Two
One from aspartate
One from free NH3
115
When are amino acids oxidized?
The cells energy charge is low
116
Fates of amino acids at a low charge energy
Amino acid is oxidized to recreate ATP
117
fates of amino acids and low glucose
the amino acids are sent to the liver to turn into glucose
118
fates of amino acids and high energy charge and lots of glucose
the amino acid is sent to the liver and turned into fat
119
what can amino acids also be used to synthesize?
synthesize protein or nitrogen containing compounds
120
what is the precursor for free NH3 and aspartate?
glutamate
121
glutamate is the precursor for aspartate and NH3 why?
conversion to alpha KG gives free NH3
| B6 holding nitrogen from glutamate forms aspartate from OAA
122
what creates a low energy charge in the muscle
exercise
123
what can exercising muscle oxidize?
(krebs ETS) oxidizes specific Amino acids to make ATP
124
exercise and macronutrients
low energy charge in muscle
125
exercise and carbs burn
glycogen breakdown
glycolysis
prep step
krebs cycle
126
exercise and fats
TAG to Free fatty acids to Beta oxidation to Krebs cycle
127
exercise and proteins
oxidative LIV GAA
| amino groups are sent to the liver in alanine
128
alanine is for
blood glucose
129
a-ketoglutarate is for
anaplerosis
130
what are plasma trends with exercise?
glutamate
| alanine
131
plasma trends with exercise concentrations effects on glutamate
decreases
132
plasma trends with exercise concentrations effects on alanine
increases
133
how much ATP turnover within skeletal muscle increase is there
100 fold
134
how much of the TCA intermediates increase
4-10 fold
135
what does the demand for ATP require
much more active krebs cycle
136
how do you turn the amino acid into a fat?
```
turn the amino acid into a ketoacid
a a ketoacid into acetyl CoA (some may turn into some other molecules that are part of the fat synthesis pathway)
make fat (acetyl CoA carboxylase, Fatty acid synthetase)
```
137
Muscle amino acids and gluconeogenesis:
starvation or not eating carbs
| exercise
138
starvation or not eating carbs
amino acid export
when blood glucose is low muscle exports amino acids for GNG
exceptions are leucine and lysine
139
exercise adn muscle amino acids and gluconeogenesis
glucose alanine cycle
during exercise muscle is releasing alanine
liver turns alanine to glucose
liver takes the amino group and converts it to urea
140
what are two amino acids that cannot turn into glucose
Leucine
Lysine
these are ketogenic
141
what are nonessential glucogenic amino acids
```
alanine
asparagine
aspartate
cystine
glutamate
glutamine
glycine
proline serine
tyrosine
```
142
what are essential glucogenis amino acids
```
arginine
histidine
methionine
threonine
valine
phenyalanine
typtophan
```
143
during starvation or low carb diet most glucose is created from
amino acids
144
what may low blood glucose be a result from
starvation
low carb intake
exercise
145
when are amino acids turned into glucose
when blood glucose is low
146
what are the most abundantly released amino acids
glutamine 50%
| alanine 30%
147
what is released more amounts then what is taken in muscle release of amino acids
alanine and glutamate
148
what is released in less amounts then what is taken in muscle uptake of amino acids?
```
BCAAs
glutamate
aspartate
aspartate
asparagine
```
149
what are most amino acids released in direct proportion to?and what are some exceptions
to their relative occurrence in muscle protein
exceptions:
BRAA, leucine, isoleucine, valine
glutamate, aspartate, asparagine, glutamine, alainie
150
during exercise what rate does glycolysis runs at?
at a race pace then that of the krebs cycle
151
what does running glycolysis faster produce
extra pyruvate to pick up the amino groups from the amino acids being oxidize
this is the reasons for increased alanine
152
what is the importance of muscle glycogen and what is it essential in
it is a fuel
it is the source of pyruvate for exporting amino groups
essential in high intensity exercise
153
what can not be called upon to build krebs cycle during exercise if pyruvate is not present to haul away the amino groups
amino acids
154
what are BRAA used for
muscles use them for fuel
155
what does muscle use out of AA
uses their nitrogen to make glutamine for export :
muscle and other tissues (except for liver) contain BR aminotransferases
over 90% of muscle amino acid uptake after a meal is LIV and glutamate
156
what is muscle intake after a meal
large uptake of BCAA and glutamate
| muscles releases glutamine more then doubles
157
large uptake of BCAA and glutamate
More then 90% of muscle amino acids uptake
The gut doesn't have a large uptake of BCAA (lacks sensitivity)
Splanchnic area constantly releases glutamate (consumes glutamine releases glutamate)
