Amino Acid Metabolism Flashcards Preview

Biochemistry 2 > Amino Acid Metabolism > Flashcards

Flashcards in Amino Acid Metabolism Deck (157):
1

Metabolism (carbs, lipicds, proteins)
FAD > FADH2
NAD+ > NADH + H+

CO2 + H2O + ATP

2

Metabolism energy of proteins

dietary proteins
tissue proteins

3

amino acids metabolism depends on what?

depends on the energy requirements of the cell

4

amino acid degradation occurs under 3 circumstances depends on what body needs

we break down amino acids"
1. protein turnover- break down our protein depends on diet
2. protein rich diet- to much in body we break down what we dont use in body
3. starvation, uncontrolled diabetes mellitus- dont have it so we use it as a fuel

5

amino acid supply:
where are amino acids stored?

not stored in the body

6

amino acid supply:
amino acids are not stored in the body:

dietary
synthesized
protein degradation

7

amino acid supply:
Excess amino acids are catabolized

Step 1: removal of amino group (nitrogen)
Step 2: carbon skeleton

8

what is the amino acid pool supplied by?

supplied by breakdown of endogenous protein dietary protein and synthesis of non essential AA

9

amino acid pool:
Free amino acids:

cells
blood
extrzcellular fluid

10

what is more abundant in the body proteins or free amino acids?

proteins are more abundant then Free Amino acids

11

What is the fate of amino acids?

Low energy charge
low glucose
high energy charge and lots of glucose

12

fates of amino acids and low energy charge

the amino acid is oxidized to recreate ATP

13

fates of amino acids and low glucose

the amino acids id sent to the liver to turn into glucose

14

fates of amino acids and high emergy charge and lots of glucose

the amino acid is sent to the liver and turned into fat

15

what can amino acids also be used to synthesize?

amino acids may also be used to synthesize protein or nitrogen containing compounds

16

Oxidation of amino acids means what?

means burning them in the aerobic system (krebs cycle and ETS) to get ATP

17

What oxidaizes most of the 20 amino acids in protein

the liver does

18

what can only oxidize significantly six?

muscle

19

When are amino acids oxidized?

when the cells' energy charge is LOW

20

amino acid catabolism (alpha amino acids)

amino group
- urea
carbon skeleton (a keto acid)
- ATP + CO2 + H2O
- glucose
-fatty acids

21

amino acid catabolism (alpha amino acids)

amino group
- urea
carbon skeleton (a keto acid)
- ATP + CO2 + H2O
- glucose
-fatty acids

22

what is the primary site for uptake of most amino acids following a meal (50-60%)?

the liver

23

what are 20% used for? and where do they stay and released?

20% for synthesis of protein; most stay in the liver while the rest are released into the plasma

24

what are 20% used for? and where do they stay and released?

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)