Protein and AA Metabolism Flashcards
1
Q
AA pools come from many different places
A
- body proteins
- dietary proteins ***most come from
- synthesized non AA
2
Q
AA pools are supplied from
A
- Food we eat
- protein turnover
- de novo synthesis
3
Q
AA are depleted by
A
- creation of nitrogen containing products
- creation of body proteins
- degradation to enter different metabolic pathways or urine
4
Q
What happens to a majority of the non recoverable AA?
A
excreted in urine
5
Q
Defects in AA resportion will cause
A
- Hartnups Dz
2. Cystinuria
6
Q
Exopeptidases
A
attack at the C- or N- (aminopeptidase) terminus
7
Q
Endopeptidase
A
attacks with the protein at a specific site by breaking internal peptide bonds
8
Q
__________ is a SELECTIVE method of intracellular proteolytic control
A
lysosome/autophagy system
9
Q
NON-SELECTIVE methofs of intracellular proteolytic control
A
- macroautophagy
- microautophagy
- Chaperonin mediated autophage
10
Q
Proteosomal degradation
A
large proteosomes cleave polyubiquitinated proteins.
11
Q
is proteosomal degradation selective?
A
Yes. Because they must be tagged with Ubiquitin.
12
Q
How does ubiquiton tag a protein?
A
It needs a carrier protein so that it can tag it.
13
Q
Method of ubiquitation:
A
- [ubiquiton ligase] will bind to the protein
- signals [ubqition carrier] to come and drop off UB.
- More are brought over
- the proteosome will now recognize for degradation
14
Q
Proteosomes are located in
A
cytoplasmic
15
Q
do proteolyitic enzymes roam around our body?
A
YES. they roam around our body as zymogens
they’re activated via proteolytic cleavage
16
Q
Essential AA
A
Phenylalanine Valine Trp Threonine Isoleucine Methionine Histidine Argining Lysine Leucine *glutamine
17
Q
At certain times, ____ and ____ can be considered essential
A
glutamine
arginine
18
Q
ketogenic AA (7)
A
Lysine and leucine
IPTT
19
Q
Both ketogenic and glucogenic (5)
A
IPTTT(all of the ones that begin with T)
Isoleucine Phe Truptophan Threonine Tyrosone
20
Q
There are ____ glucogenic AA
A
18.
13 true glucogenic
then there are 5 that can be both (IPTTT)
21
Q
OAA can make what AA
A
aspartate
22
Q
Aspartate can make what AA
A
Asparagine
methionine
Threonine
Lysine
23
Q
DIRECT biosynthetic precursor of isoleucine
A
threonine
24
Q
Pyruvate makes which AA?
A
Alanine
valine
leucine
25
R5P can make
histidine
26
Alpha keto glutarate can make
Glu--> Glu, Arg, Pro
27
3-phosphoglycerate can make
Serine
| Serine can then make cysteine and glycine
28
What makes cysteine and glycine?
Serine will make both cysteine and glycine
29
Proteoylsis
the degradation of proteins so that they can be absorbed.
30
Proteins that are misfolded will be discarded in wha tways
1. microautophagy
2. macroautophagy
2. chaperonin assisted autophagy
31
How do we activate trypsinogen
enterokinase will convert trypsinogen--> tryspin
32
Howe do we activate chymotrypsinogen
1. First, we active trysinogen using enterokinase
| 2. trypsin that is made will then come and active chymotrypsinogen
33
What is the P and T in PVT TIM HALL
Phenylalanine
| Tryptophan and Threonine.
34
What is transanimation?
Transanimation is the shuffling of amine groups
an amino group is transferred to a keto-acid.
35
What kinds of enzymes facilitate transanimations?
transaminases
| aminotransferases
36
Transaminases require what co-enzyme?
PLP
| pyridoxyl-5-phosphate
37
PLP is a derivative of what?
vitamine b6
38
____ and ___ are tests of liver function. They must have coenzyme ____
ALT- alanine transaminase
AST- aspartate transaminase
PLP (pyridoxyl-5-phosphate.
39
Metabolism of Gln, Glu, Arg, Pro, and His
They are all converted to Glu.
Glu is converted alpha ketoglutarate in 3 ways
40
What 3 ways are Glu converted to alpha ketoglutarate?
1. Release NH4+ via oxidative deamination by glutamate DH
2. Transfer amino group to [pyruvate] by ALT
3. Transfer amino group to [OAA] by AST
41
Gln--> glutamate loses a amino group because of what?
nitrogen trap method.
42
What is PLP
pyridoxyl 5 phosphate.
It is a coenzyme for transaminases.
It is a derivative of vitamin b6
43
Methionine is converted to _____ and eventually _______.
Methionine is converted to HOMOCYSTEINE and eventually succinyl co-A
44
Homocysteinuria
Homocystinuria occurs when there is a buildup of homocysteine
45
Homocysteinuria is due to
1. defect in cystathione B synthase (an enzyme that needs PLP)
2. vita B6, B12 and folic acid deficiencies
46
Defects in cystathione b synthase can cause
homocystenuria.
47
what happens if we have a deificieny in PLP
defects in PLP can worsen the problem and cause hyperhomocysteinuria, when homocysteine is present in urea.
we will be unable to make cysteine
48
most affected organs of homocysteineuria
eye
skeletal muscle
CNS
vascular
49
How is threonine, valine and isoleucine broke down?
propionyl coA--> methylmalonyl coA--> succinyl coA
similar to how odd number chain FA are broken down!!!
50
What are the BCAA (branch chain AA)?
Valine
Isoleucine
Leucine
51
What are different about branch chain AA?
Valine, isoleucine and leucine.
Branch chain AA cannot be metabolized in the liver because there is no aminotransferase.
Instead, they are broken down in the muscle, kidney and brain.
52
What AA enter the TCA cycle at succinyl coA?
TIM V
Threonine
Isoleucine
Methionine
Valine
53
When are BCAAs used for NRG?
BCAAs are used for energy during prolonged exercise or fasting
54
Maple Syrup Disease
Maple syrup disease occurs when we have a defective BCKD.
As a result, BCAAs (valine, isoleucine and leucine) will appear in the urine and cause a syrupy smell.
55
_______________ is high in the jewish and amish population
Maple syrup dz
56
Phenylalanine is converted to _______ via ______________
Phe is converted to Tyrosine via phenylalanine hydroxylase
57
What enzyme converts Phe to Tyrosine?
Phenylalanine hydroxylase
58
What happens when phenylalanine hydroxylase is not working?
when phenylanine hydroxylase is not working,
we will have a buildup of Phe. Phe is then broken down to phenylacetate and phenylactate
59
Phenyllactate will cause
smelly urine
60
Phenylacetate will cause
disruption of neural transmission
61
if you have PKU; you should avoid
Phe,
| because you cannot process it.
62
What enters the TCA cycle at fumurate?
Phe
Tyrosine
Asp
63
What enters the TCA cycle at OAA?
Asn
| Asp
64
Why is tryptophan so important
it makes serotonin, which makes melatonin (sleep)
65
high amounts of _____ is indicative of carcinoid tuumors
serotonin
66
What AA derivates makes serotinin and melatonin
Trp
67
Tyrosine is important because it particpates in the production of
thyroid hormones, DA, NA, Epi
68
If tyrosine hydrolase is inhibited, what happens?
we will have deficits in DA, NA and EPi
69
What enzyme converts tyrosine to DA, EPI and NE
Tyrosine hydroxylase
70
Parkinsons
deficit in DA because of mutation in tyrosine hydroxylase
71
Albanism
Albanism is caused by a deficit in tyrocinase, the enzyme that converts tyrosine--> melanin
72
What enzyme converts _______ to melanin?
tyrocinase converts tyrosine to melanin
73
______ is a protein made by the thyroid to help with the production of T3 and T4
thyroglobulin
74
How can we treat pts with hyperthyroidism?
We give patients carbimazole or polythiouracil, which blocks the iodination of thyroglobin to decrease amounts of T3 and T4
75
How do we remove ammonia (NH3) in the brain?
Ammonia is removed as Glu and Gln in the brain using [glutamine synthase]
76
What enzyme removes ammonia in the brain
glutamine synthase
77
How do we remove ammonia from all other tissue besides the brain?
Gln and alanine
78
do we excrete NH3 or NH4
NH4
79
Removal of excess NH4 from the brain
in the brain:
we have alpha ketoglutarate (ammonium joins)--> Glu (NH3)--> Gln (via glutamine synthase)
leaves the brain and goes to the liver
Gln is processed and NH4 is released
80
Removal of excess NH4 from the muscle
RMBR from the muscle it is removed as Ala and Glu
1. Glucose--> pyruvate in glycolysis
2. A transanimation reaction will transfer the amino group to alanine
Ala will then go to the liver and a transmino reeaction will cause the NH4 to be released
81
What is a transanimation
the transfer of an AA from an alpha AA to a alpha ketoacid
82
What are 2 byproducts of processing AA?
ornithine and citrulline
83
Ammonia toxicity
excess ammonia because of liver failure or urea cycle disorder.
This is bad because ammonia is very toxic and can permeate membranes. NH4 cannot
84
Ammonia toxicity can cause what?
1. mitochondria dsfx
2. deplete our glutamate (so no GABA)
3. pH imbalance leading to swelling of astrocytes in the braing, leading to edema nad HTN
85
What is phosphocreatine
the nrg storage in our muscle
86
What is phosphocreatine made up of
3 AA:
arginine,
glycine and methionine
87
How is phosphocreatine made
1. in the kidney:
arginine joins glycine to form guanidinoacetate
2. In the liver
methionine will joing guanidinoacetate to form CREATINE!
2. Creatine is phosphorylated via creatine kinase to make creatine phosphate. .
88
What is the ready to go protein NRG in the muscle?
creatine phosphate
89
Do we keep all of our creatine phosphate?
no. a small amount of it is converted to creatinine and excrteted in our urine
90
How can we test for kidney dysfunction and muscle degeneration?
elevated levels of creatinine in the urine.
91
What enters succinyl coA?
Threonine
Iso
Met
Valine
Threonine, met and val are all processed the same way.
met--> homocysteine and eventually succinyl coA
