Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochem 6200 > Lecture 8 Amino Acids > Flashcards

Lecture 8 Amino Acids Flashcards

1
Q

Nitrogen Metabolism

A

Amino acid synth, amino degradation, derivatives of AA, urea cycle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Energy used for

A

Heat, mechanical movement, electrical work, chemical energy can be stored or used as food.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Metabolism

A

Release of energy, water, CO2.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Anabolism

A

Building

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Catabolism

A

Breaking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Anabolic reactions

A

Glucose to glycogen, Glycerol+fatty acids to triglycerides, amino acids to proteins. Most of this happens in the liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Catabolism

A

Glycogen to glucose, triglycerides to glycerol + fatty acids, proteins to AAs (obtain essential AAs this way). Most of this happens in the liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

AA breakdown

A

Ammonia byproduct.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Digestion

A

Carbs - glucose (+other monosaccharides)
Fats - triglycerides (glycerol, fatty acids)
Proteins - aas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Using aas as energy

A

First you have to get rid of nitrogen. AAs feed into becoming pyruvate (3 carbon - used for glucose production), acetyl CoA (2 carbon, not for glucose). TCA cycle and ETC can be used later from these.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Breaking down nutrients

A

AAs and glycerol can be converted to pyruvate (glucose later). Needed for CNS and RBCs. Lean tissue goes when body runs out of glucose. Adequate carbs prevent this. Fatty acids are converted to Acetyl-CoA (not for glucose).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Pyruvate’s Options

A

Quick energy - convert to lactate (anaerobic). Sustained for just a few minutes.
SLower energy - convert to acetyl CoA - aerobic.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Cori Cycle

A

Lactic acid travels to the liver

–the liver converts it back to glucose –This is called the Cori cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Pyruvate to Acetyl CoA

A

If o2 is available. Pyruvate enters mitochondria, –produce 2 acetyl CoA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Glucogenic AAs

A

Convert to pyruvate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Ketogenic AAs

A

COnvert to acetyl CoA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

AAs breakdown

A

they can be used for energy or converted to fatty acids and stored as triglyceride.
–Some enter the TCA cycle directly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Dietary protein

A

Dietary protein is the main source of amino acid. In the process of digestion, proteins are broken down to free aa in the gastrointestinal tract. The resulting alpha-keto acid is then used as fuel, or as a biosynthetic intermediate.
Unlike carbohydrates and lipids, aa do not have a dedicated storage form equivalent to glycogen or fat.
When aa are metabolized, the resulting excess nitrogen must be excreted.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Transamination

A

Remove amine group from AAs in liver.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Protein digestion

A

Stomach - HCl breaks down, denatures, small peptides. Intestines - other proteases get it to AAs and some dipeptides. Transport across small intestine lining.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

AAs to body proteins, Glucose to glycogen

A

Reversible.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

AA catabolsim

A

Removal of amino group, use of nitrogen in synth of new nitrogen compounds, passage of nitrogen into urea cycle, incorporation of carbon atoms into compounds for CAC cycle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Our body does not store

A

Nitrogen containing compounds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Transaminase

A

Use alpha ketoglutarate as amino group nitrogen acceptor. This is converted to glutamate.

25
Q

Transaminase

A

Exchange amino group with carbonyl. No net loss of N2.

26
Q

Alanine can be converted to

A

pyruvate and glutamate from alanine and oxoglutarate (all 3 carbon atoms, all of these conversion reactions are bidirectional).

27
Q

Glutamate

A

All amino groups go through glutamate. Transaminase reactions are easily reversible. Concentrations determine where it goes.

28
Q

Transaminases

A

Equilibriate amino groups among available alpha keto acids.

29
Q

Nitrogen

A

Although the amino N of one amino acid can be used to synthesize another amino acid, N must be obtained in the diet as amino acids (proteins).

Proceed through urea cycle before excretion (processing occurs in liver).

30
Q

Urea Cycle

A

Ammonia is highly toxic to living organisms and must be eliminated safely. Fish excrete ammonia through their gills directly into the surrounding water and mammals converts ammonia to non-toxic urea via the urea cycle.

The conversion of ammonia to urea takes place in the liver. From there urea is transported to the kidneys and transferred to urine for excretion.

31
Q

AA degradation

A

Transamination
Oxidative Deamination
Removal of a molecule of water by a dehydratase

32
Q

Oxidative Deamination

A

he oxidative removal of the amino group, resulting in keto acids and ammonia

33
Q

Removal of a molecule of water by a dehydratase

A

serine or threonine dyhydratase; this reaction produces an unstable, imine intermediate that hydrolyzes spontaneously to yield an α-keto acid and ammonia

34
Q

Glutamate Dehydrogenase

A

Catalyzes rxn that removes N from the amino acid pool. Takes N from glutamate to form alpha-ketoglutarate (now this can go back to grab a different ammonia).

35
Q

Serine Dehydratase

A

Pyridoxal phosphate dependent

Product is pyruvate

Remove H20, leaving unstable intermediate. This will spontaneously remove ammonia and form pyruvate.

36
Q

Serum urea

A

BUN (blood urea nitrogen). Monitored in patients with amino acid metabolism disorders or renal problems. Measure the action of urease by monitoring ammonia product with a color reagent.

37
Q

Monosodium Glutamate - MSG

A

Food additive. Can cause weakness, tingling and a sensation of warmth in the face and upper torso. Symptoms generally last about 30 minutes. No permanent damage, but could trigger bronchospasms (asthma).

38
Q

Glutamic acid

A

Also a neurotransmitter - can be decarboxylated to form GABA, another neurotransmitter.

39
Q

Deamination

A

Oxidative, nonoxidative

40
Q

Alanine as a carrier

A

Transported from peripheral tissues to liver, converted to pyruvate with nitrogen incorporated into urea
Pyrovate can be used to produce glucose (gluconeogenesis)
This glucose-alanine cycle allows the net conversion of amino acid carbons to glucose

Carbons are returned to peripheral tissues as glucose
Alanine and glutamine are released in similar amounts from muscle
Account for about 50% or amino acids released by muscle into the blood

41
Q

Alanine and Glutamine flow

A

The amount of alanine and glutamine released far exceeds the proportion of these Aas in muscle proteins
Large amounts of remodeling of protein-derived amno acids occurs by transaminations

42
Q

Nitrogen excretion

A 
No storage
Need to ingest excess
Ammonia toxic
NH4+
-Excrete excess
Ammonia, NH4+
Aquatic animals
(ammonolitic organism)
Uric Acid
Birds and reptiles
(uricotelic organisms)
Urea, H2N-(CO)-NH2
Terrestrial vertabrates
(ureotelic organisms)
43
Q

Aquatic animals

ammonolitic organism

A

Ammonia, NH4+

44
Q

Birds and reptiles

uricotelic organisms

A

Uric Acid

45
Q

Terrestrial vertabrates

ureotelic organisms

A

Urea, H2N-(CO)-NH2

46
Q

Urea cycle

A

First metabolic cycle detected. Krebs & Henseleit. Urea H2N-(CO)-NH2, 2 nitrogens
1 from ammonia through carbamoyl phosphate
NH3 + HCO3- + 2ATP
1 from Aspartic acid
α-ketoglutarate + NH4+ + NADH + H+
Carbon from bicarbonate (unfixed)
Urea cycle also excretes bicarbonate breakdown product of carboxylic acids

Starts in mito

47
Q

Inherited disorders of urea cycle

A

Loss of cycle catastrophic
Ammonia toxic to brain coma
See with liver failure
Do not see genetic diseases with total loss

Genetic partial deficiencies retardation
Treatment with low protein diets
Supplement with keto-acids
Mops up excess NH3
If choose wisely, can get essential amino acids made (e.g., α-ketoisovalerate valine)

48
Q

Treatment of genetic deficiencies in urea cycle enzymes

A

Aromatic groups can help

49
Q

AA formation

A

First step required

transamination→ glutamate or aspartate

50
Q

Glucogenic

A

Increase glucose - certain AAs are both glucogenic and ketogenic.

51
Q

Ketogenic

A

Increase ketone bodies.

52
Q

Maple syrup urine disease

A

Inherited. Loss of the α-amino group, followed by oxidative decarboxylation of the resulting α-keto acid to produce a CoA derivative
Decarboxylation catalyzed by branched-chain keto acid decarboxylase (IM of mitochondria)
Untreated lead to both physical and mental retardation
Defect can be managed with a low-protein diet or modified diet or supplementation with high doses of thiamine pyrophosphate

53
Q

Phenylketonuria

A

Deficiency of phenylalanine hydroxylase. Untreated leads to excretion of phenylpyruvate and phenyllactate. Can result in severe retardation. Individuals, very light skin, unusual gait, stance

54
Q

Alkaptonuria (black urine disease)

A

Deficiency in phenylalanine-tyrosine pathway, the enzyme that catabolizes the oxidation of homogentisic acid
Homogentisic acid accumulates and is excreted in the in urine (1 in 1,000,000 births). This compound gives urine a dark color
Individual: dark pigment in cartilage tissue, with subsequent tissue damage, and severe arthritis
Only symptomatic relief

55
Q

Albinism

A

Lack of pigmentation (amino acid pathways). Blue eyes, light blond hair. Lack enzyme tyrosinase.

56
Q

Tyrosinase

A

2-step hydroxylation of tyrosine to dihydroxyphenylalanie (DOPA) and further oxidation to a quinone, a precursor of melanin

57
Q

LSD

A

derived from tryptophan and serotonin.

58
Q

Polyamines

A

Exactly what it sounds like. Ornithine is a precursor. Ornithine decarboxylase upregulated in a wide variety of cancers - ODC is the rate limiting step in polyamine synthesis. Drugs targeting ODC have been used in cancer treatment. In essence, inhibit polyamines, inhibit growth.

Biochem 6200 (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions