TBL Prep Flashcards
(104 cards)
1
Q
What are the essential amino acids?
A
HILL My PT TV Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine
2
Q
What is the weird reason that we need amino acids?
A
substrate for heme, purine, pyrimidine, melanin
3
Q
What are the 5 important cofactors in amino acid metabolism?
A
- THF
- SAM
- Biotin
- THB
- Pyridoxal Phosphate (PLP)
4
Q
Where is THF from? What does it do?
A
synthesized by bacteria
transfers single carbons
5
Q
How is SAM synthesized?
A
Synthesized from ATP & Methionine
6
Q
What does SAM do?
A
transfers methyl groups
7
Q
What does biotin do?
A
transfers CO2
8
Q
What is THB involved in?
A
tyrosine synthesis
involved in oxidation reaction
Remember: “think outside the BOX”
9
Q
What does PLP do? What types of reactions is it involved in? What is it a coenzyme for?
A
holds nitrogen–>how cute
involved in transaminase reaction
coenzyme for vitamin B6
10
Q
Once again, what are the energy results of the TCA cycle?
A
3 NADH=9 ATP
1 GTP=1 ATP
1 FADH2=2 ATP
11
Q
Which enzyme of TCA is bound to the inner mitochondrial membrane?
A
succinate dehydrogenase
12
Q
What part of the TCA cycle does excess EtOH feed in to? How?
A
Acetyl CoA!
EtOH–>Acetaldehyde–>acetic acid–>acetyl CoA
13
Q
What are the 2 effects of excess citrate? Where does it go?
A
Gets out of the mitochondria and inhibits glycolysis & goes into Fatty Acid Synthesis.
14
Q
What is the reaction for the synthesis of glutamate?
A
alpha-KG + NH4+ + NADPH–>Glutamate +NADP+ + H2O
Enzyme: glutamate dehydrogenase
15
Q
When does the synthesis of glutamate occur? When does it occur?
A
when there are toxic amount of ammonia, mainly in the liver…
16
Q
What is the reaction for the formation of glutamine?
A
Glutamate + ATP + NH3–>Glutamine
Enzyme: glutamine synthetase
17
Q
What is the reaction for the formation of glutamate from glutamine?
A
Glutamine –> Glutamate + NH4+
Enzyme: glutaminase
18
Q
How is non-toxic version of ammonium transferred around?
A
thru glutamine
19
Q
What is the most abundant circulating AA?
A
glutamine!
20
Q
Glutamine is _____ donor in many ____ reactions.
A
nitrogen donor
many synthesis reactions
21
Q
Which of the following can move across a cell membrane:
glutamine
glutamate?
A
glutamine!!
22
Q
What is the reaction for making alanine?
A
Pyruvate + AA –>Alanine + alpha keto acid
Enzyme: ALT: alanine transaminase
23
Q
T/F Transaminases are used in irreversible reactions.
A
FALSE
they are reversible reactions, highly reversible
24
Q
What cofactor do all transaminases require?
A
PLP found in Vitamin B6
25
Which enzyme's levels are checked if you suspect liver damage?
ALT
26
What is the reaction for the formation of aspartate?
OAA + Glutamate-->Aspartate + alpha KG
| Enzyme: GOT: glutamate-OAA transaminase
27
What is the reaction for the formation of asparagine?
Aspartate + ATP + Glutamine-->Asparagine + Glutamate
| Enzyme: Asparagine Synthetase
28
Is there a reverse reaction for asparagine? If so, what is it?
YES, glad you asked.
Asparagine --> Aspartate + NH4+
Enzyme: asparaginase
29
Leukemia patients are sometimes unable to synthesize _____. Thus, _____ is sometimes used as a treatment.
asparagine
| asparaginase is used as a treatment
30
Asparagine is often ________.
glycosylated
31
What is an enzyme that humans don't express involved in AA synthesis?
asparaginase
32
What is the reaction for the formation of serine?
3PG + Glutamate --> Serine + alpha KG + NADH
33
What is the reaction for the formation of glycine?
Serine + THF--> Glycine
34
What is the reaction for the formation of methionine?
Homocysteine + methyl-THF --> Methionine + THF
| uses Vit B12
35
How do you make homocysteine?
via Met + ATP-->SAM-->SAHcys-->Homocysteine
36
What is the intermediate b/w homocysteine & Cysteine?
cystathionine
37
Which AA must be added in to make cystathionine?
Serine!
38
How do you make cystathionine?
Homocysteine + Serine --> Cystathionine
Enzyme: Cystathionine Synthase
Requires: PLP
39
How do you make cysteine from cystathionine?
Cystathionine --> Cysteine
Enzyme: cystathionase
Requires: PLP
40
What causes homocystinuria? What are the effects of this condition? What are its treatments?
```
deficiencies in cystathionine synthase
or cystathionase
mental deficiency
vascular thrombosis
thinning & lengthening of long bones
osteoporosis
Treatments: dietary, vitamin
```
41
What is the reaction for the formation of tyrosine?
Phenylalanine + THB-->Tyrosine + DHB
| Enzyme: Phenylalanine hydroxylase
42
What does tyrosine go on to form? Which enzyme is required for this to happen?
goes on to form melanin
| Enzyme: tyrosinase
43
Once THB-->DHB how do you renew it again?
DHB-->THB
Requires: NADH
Enzyme: DHB reductase
44
What happens when you have too much phenylalanine?
You get formation of phenylketones
| Then you can get PKU
45
What are the symptoms of PKU? What are the treatments?
Symptoms: mental retardation, light skin color
Treatments: dietary, no aspartame
46
What is proline made from? What feed in does it require?
made from glutamate
| requires NADH
47
What types of ubiquination make for urgent degradation?
longer chains
48
What type of ubiquination makes for fast degradation?
when the N-terminus has destabilizing things
LADS are FAST
leucine
arginine
49
What type of ubiquination makes for slow degradation?
when the N-terminus has stabilizing things
PMS makes you SLOW
proline
methionine
50
What causes Alzheimer's & Parkinson's?
formation of protein structures in neurons
51
What causes cystic fibrosis?
rapid degradation of chloride channels
52
What causes Liddle's Syndrome? What is the significance of this?
the sodium channel that is inserted into the nephron isn't degraded...
this leads to excess sodium absorption
this causes early-onset HTN
53
What 2 things cause negative nitrogen balance?
stress hormones
| cytokines
54
Which 3 types of people will have a positive nitrogen balance?
children
pregnant women
body builders
55
What is nitrogen balance?
Nitrogen balance is when Nitrogen Intake = Nitrogen loss
56
What defect leads to oxaluria type I?
a deficiency of glycine transaminase
| Can't take glyoxylate-->glycine
57
What defect leads to nonketotic hyperglycinemia?
A lack of glycine cleavage enzyme
| Can't break down glycine!
58
What defect leads to homocystinuria?
A lack of cystathionine synthase
Can't make cysteine
get a buildup of homocysteine
59
What enzyme deficiency leads to PKU?
phenylalanine hydroxylase
60
What causes tyrosinemia type II?
a defect in tyrosine aminotransferase
61
What causes tyrosinemia Type I?
a defect in fumarylacetoacetate hydroxylase
| get a buildup of an intermediate instead of fumarate!
62
WHat cause alkaptonuria?
deficiency in homogentisate oxidase
| get a buildup of an intermediate instead of fumarate
63
What causes histidinemia?
a deficiency of histidase
64
What intermediate accumulates w/ a folate deficiency?
FIGLU
| formimino glutamic acid
65
What defect leads to methylmalonic aciduria?
a defect in methylmalonyl CoA mutase
| can't make succinyl CoA
66
What causes maple syrup urine disease?
a deficiency of branched chain alpha keto acid dehydrogenase complex
67
How do you degrade branched AA?
transamination & then oxidative decarboxylation
68
What are some examples of breakdown products of branched AA catabolism?
propionyl CoA
Acetyl CoA
Acetoacetate
69
Which AA are catabolized in the intestinal mucosal cells?
glutamate
| glutamine
70
Where are most AA metabolized?
in the liver
71
How are branched chain AA metabolized?
they leave the liver & go to muscle for the transamination reaction; then they return to the liver for oxidative decarboxylation
72
What is the major source of AA during fasting?
muscle protein!
73
2 AA go to glucose thru gluconeogenesis during fasting...which AA? Where do they go to do this?
glutamine-->kidneys & intesines
| alanine-->liver
74
In the degradation of phenylalanine...what bad things can happen? What accumulates in each case?
deficiency of phenylalanine hydroxylase
deficiency of DHB reductase
**In both cases: phenylalanine accumulates
75
What condition does a deficiency of phenylalanine hydroxylase cause? What are the symptoms?
PKU (classical)
| Mental Retardation
76
What condition does a deficiency of DHB reductase cause?
PKU (non-classical)
| Mental Retardation
77
In the degradation pathway of tyrosine...what can go wrong? What accumulates in each case?
a deficiency of homogentisate oxidase (homogentisate acid)
a deficiency of fumarylacetoacetate hydroxylase (fumarylacetoacetate)
a deficiency of tyrosine aminotransferase (tyrosine)
78
What condition does a deficiency of homogentisate oxidase & an accumulation of homogentisate acid cause? What are the symptoms?
Alcaptonuria
black urine
arthritis
79
What condition does a deficiency of fumarylacetoacetate hydroxylase & an accumulation of fumarylacetoacetate cause? What are the symptoms?
Tyrosinemia I
Liver Failure
Early Death
80
What condition does a deficiency of tyrosine aminotransferase and an accumulation of tyrosine cause? What are its symptoms?
Tyrosinemia II
| neurological defects
81
In the degradation of methionine...what can go wrong? What accumulates?
a deficiency of cystathionase (cystathionine)
| a deficiency of cystathionine synthase (homocysteine)
82
What condition does a deficiency of cystathionase & an accumulation of cystathionine cause? What are its symptoms?
Cystathionuria
| Benign
83
What condition does a deficiency of cystathionine synthase & an accumulation of homocysteine cause? What are its symptoms?
homocysteinuria
| cardiovascular & neurologic problems
84
In the degradation of glycine...what can go wrong? What accumulates?
a deficiency of glycine transaminase (glyoxylate)
| a deficiency of glycine cleavage enzyme (glycine)
85
With a deficiency of glycine transaminase & an accumulation of glyoxylate...what condition results? What are its symptoms?
Primary Oxaluria Type I
| Renal failure w/ stone formation
86
What condition is caused by a deficiency of glycine cleavage enzyme & an accumulation of glycine? What are its symptoms?
Hyper Glycinemia
| Mental Retardation
87
In the degradation of branched AA what can go wrong & what accumulates?
a deficiency of branched chain alpha keto acid dehydrogenase (alpha keto acids)
88
What condition is caused by an accumulation of alpha keto acids? What are its symptoms?
Maple Syrup Urine Disease
| Mental Retardation
89
What are the 3 branched chain AA?
LIV:
| Leucine, Isoleucine, Valine
90
What is the purpose of the urea cycle?
to get rid of NH4+, which is a neurotoxin.
91
What happens to urea in the case of renal failure?
the BUN (urea in the blood) rises sharply: called uremia
92
How can urea cause kidney stones?
a bacteria enzyme in the urine can cleave urea...this has 2 effects: alkalinizing the urine & precipitating out magnesium ammonium phosphate
93
If you have an inherited deficiency of some of the urea cycle enzymes...what happens?
Hyperammonemia & Encephalopathy
| lethargy, vomiting, irritability
94
During failure of the urea cycle...why do you have ATP deficiencies?
alpha KG is converted into glutamine
95
What is the therapy for urea cycle enzyme deficiencies?
limit protein intake
remove excess ammonia
replace urea cycle intermediates
maybe liver transplant
96
What is the first step in the urea cycle? Where does it occur?
Liver, mitochondrial matrix
NH4+ + 2ATP + CO2-->Carbamoyl Phosphate
Enzyme: carbamoyl phosphate synthetase I
97
What does a buildup of carbamoyl phosphate do?
leads to orotate in your urine
98
Once you have carbamoyl phosphate in the mitochondrial matrix of the liver...what is the next step?
Ornithine combines w/ carbamoyl phosphate in the mitochondrial matrix to make citrulline.
Enzyme: ornitine transcarbamylase
99
What do you do with your citrulline?
Citrulline + ATP + Aspartate-->Arginosuccinate
| Enzyme: Arginosuccinate Synthetase
100
Where did you get the aspartate for the last step?
From the TCA cycle? It was shoved into the cystol from the mitochondrial matrix...
101
After you have arginosuccinate...what is the next step?
Arginosuccinate-->Arginine + Fumarate
| Enzyme: Arginosuccinate Lyase
102
What happens to the fumarate you just threw off?
It is converted into malate & shunted back into the mitochondrial matrix to become a part of the TCA cycle.
103
Now that you have arginine...what happens?
Arginine-->Ornithine & kicks off a urea
Enzyme: arginase
**note the ornithine will go & combine w/ the carbamoyl phosphate...
104
HOw many ATP does one urea cycle require?
4 ATP
