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Enzymes > Tough ones > Flashcards

Tough ones Flashcards

1
Q

Where does Q get it’s ammonium from?

A

NH4

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2
Q

What is the role of ALT in starvation?

A

Takes pyruvate generated in muscles and converts it to alanine for transport to the liver

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3
Q

N (when produced from Q) gets it NH4 from where?

A

From Q

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4
Q

What is the enzyme that catalyzes the reaction of glycine to serine?

A

Serine-hydroxymethyl transferase

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5
Q

What is the most oxidized form of THF?

A

N10

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6
Q

What is the most reduced form of THF?

A

N5

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7
Q

What are the molecule that donate to the one carbon pool?

A

Formaldehyde, formate, S, G, H

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8
Q

What is the cause and symptoms of Homocystieneuria?

A

Defect in Cystathinoine beta synthase

Lens dislocation, MR, thromboembolism

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9
Q

What are the symptoms of PKU? Treatment?

A

MR, SZs, rash

Low F and Y diet

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10
Q

Which amino acids serve as carbon donors in the blood?

A

A and Q

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11
Q

HHF6 lowers the activity of what other enzyme? What is this involved in?

A

N-acetyl glutaminase, which lower the N-acetyl Q production an the urea cycle.

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12
Q

A defect in the glycine cleavage system will result in what condition?

A

Glycine encephalopathy

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13
Q

Biotin is needed for what reaction?

A

Propionyl-coa to d-methylmalonyl-coa via propionyl coa decarboxylase

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14
Q

There are only two reactions in the body that require B12. Which are they?

A

Propionyl to succinyl-coa reaction

Homocystine to methionine reaction

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15
Q

The ONLY reaction in the body that can oxidize N5-methyl THF is what reaction? What variant of THF is produced in the process?

A

THF

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16
Q

What is the chemical responsible for he discoloration of alkaptonuria?

A

Benzoquinone

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17
Q

Tyrosenemia I is the result of a defect in fumarylacetoacetate hydrolase. What is produced INSTEAD of fumarate and acetate?

A

Succinyl acetone

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18
Q

Which amino acids can undergo deamination without an aminotransferase?

A

THCS

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19
Q

In the intestinal renal axis, what amino acid is picked up? What is it then converted to?

A

Q, then citrulline, then R

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20
Q

There are two compounds given to someone with urea cycle issues. Name them, and the amino acids they reaction with.

A

Phenyl-butryrate reactions with glutamine

Benzoate reacts with glycine

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21
Q

Name the enzyme that produces GABA from E, and Histamine from H

A

Pryidoxal phosphate

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22
Q

FA oxidation/ketone synthesis increases transcription for related enzymes through what system?

A

PPRE

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23
Q

Gluconeogenesis stimulate transription of enzymes through what?

A

CRE

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24
Q

Insulin induces transcription of lipid synthesis enzymes via what?

A

SRE

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25
Q

Insulin represses transcription of gluconeogenesis enzymes via what?

A

IRE

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26
Q

The enzyme IDO converts what to what in which pathway?

A

W to N-formylynurine in the synthesis of niacin

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27
Q

How does the enzyme IDO contribute to cancer?

A

Excess activity leads to the blocking of T cell action on cancer cells

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28
Q

A defect in carbomoyl synthetase I leads to what condition?

A

Hyperammonemia

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29
Q

A defect in Ornathine transcarbamoylase leads to what condition?

A

Hyperammonemia

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30
Q

A defect in arginosuccinate synthetase leads to what condition?

A

Citrullinemia

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31
Q

A defect in Arginosuccinate lyase leads to what condition?

A

Arginosuccinate acid uria

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32
Q

A defect in Arginase leads to what condition?

A

Hyperarginemia

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33
Q

What enzyme catalyzes the transfer of Glutathione to chemicals for breakdown?

A

Glutathione s-transferases

34
Q

What are three symptoms common to DM patients?

A

Fasting hypoglycemia
Hyperlipidemia
Gluconeogenesis from muscles

35
Q

Why is there hyperlipidemia in DM patients?

A

Insulin is either ineffective at inhibiting HSL or not present.

36
Q

What are the two main transcription changes brought about by insulin?

A

Increases in FA synthetase

Decrease in PEP carboxykinase

37
Q

AIP is the result of a defect in what enzyme? What are the symptoms?

A

Defect in PBG deamidase. Acute abdominal pain, dark red urine, and neuro symptoms

38
Q

PCT is the result of a defect in which enzyme? Symptoms?

A

UPG III decarboxylase.

Photosensitivity, pink urine

39
Q

What enzymes in the heme cycle does Pb inhibit?

A

ALA synthase and Ferrochelatase

40
Q

What gives urine and stool their characteristic color?

41
Q

How will PREhepatic jaundice present in regards to bilirubin in the serum, urine, and stool?

A

Elevated unconjugated bili in blood

No change in urine or stool

42
Q

How will HEPATIC jaundice present in regards to bilirubin in the serum, urine, and stool?

A

Increase is unconjugated bili in the blood

Lower amount of bili in urine and stool

43
Q

How will POSThepatic jaundice present in regards to bilirubin in the serum, urine, and stool?

A

Increase in conjugated bili in the blood
Stool bili lower
Urine bili way higher

44
Q

PRPP is synthesized from what substrate and via which enzyme?

A

RIbose-5-phosphate

PRPP synthase

45
Q

What is the enzyme that comitted PRPP to purine synthesis? What is the product?

A

Amidoribosyltransferase

PRA

46
Q

What are the four components that the purine de-novo synthesis pathway require?

A

Amino acids (GED)
CO2
N10 formyl THF
ATP

47
Q

What is required for AMP synthesis? For GMP?

A

GTP and ATP respectively.

48
Q

AMP and GMP are phosphorylated by what enzymes?

A

nucleotide mono(di)phosphate kinases

49
Q

PRPP synthetase in inhibited by what?

A

ADP and GDP

50
Q

What are the inhibitors and activators of Amidoribosyl transferase?

A 
Inhibitors = GMP, AMP,
Activator = PRPP
51
Q

Why does EtOH consumption worsen symptoms of gout?

A

Liver damage = increased ATP turnover, lactic acid production competes with uric acid for excretion

52
Q

What is the treatment for gout? What does the chemical used get metabolized into?

A

Allopurinol

Oxypurinol

53
Q

Ortic acid uria is the result of a defect in what enzyme?

A

UMP synthase

54
Q

UMP synthase is a combination of which two enzymes?

A

Oratate phosphoribosyl transferase and OMP decarboxylase

55
Q

CAD is a combination of which three enzymes?

A

Carbamoyl phophate sythetase
Aspartate transcarbamoylase
Dihydroorotase

56
Q

Megaloblastic anemia that responds to Folate and B12 is the result of what? If these do not produce a response, then what is responsible?

A

B12 deficiency (acts on Homocysteine to methionine rxn and THF generation–no purines)

Ortic acid uria if not responsive (no pyrimidine synthesis due to UMP synthase defect).

57
Q

Hydroxyurea blocks which reaction?

A

Ribonucleotide reductase

58
Q

Deoxyribonucleotides are producted via which enzyme?

A

Ribonucleotide reductase

59
Q

Ribonucleotide reductase requires what molecule to reduce ribonucleotide?

A

Thioredoxin

60
Q

Thioredoxin is reduced back from it oxidative state via which enzyme? Which electron donor molecule does this require?

A

Thioredoxin reductase.

NADPH

61
Q

Which dNTP regulates all dNTP production

62
Q

How is CTP generated?

A

From UTP via CTP synthase

63
Q

SCID is a defect in what enzyme?

A

Adenosine deamiase

64
Q

A defect in adenosine deaminase results in the accumulation of adenosine in the degradation of AMP. What disease does this result in?

65
Q

True or false: CMP, TMP, UMP are all phosphorylated by mono(di)ribonucletoide phosphate kinases to produced CTP, TTP and UTP.

A

FALSE

TMP, TDP, and TTP do no exist in the body–only dTMP

66
Q

5-fluorouracil is converted into what, then what, and inhibits what?

A

FUMP, FdUMP, and irreversibly binds Thymidylate synthase

67
Q

Beta-alanine is produced from what?

A

Degradation of the pyrimidines UMP, CMP, and dCMP

68
Q

Betaisobutryate is produced from what?

A

Degradation of the pyrimidine dTMP

used as a measure of DNA turnover

69
Q

Purine bases (guanine, hypoxanthine, and adenine) are converted to their nucleosides by which enzymes?

A

Hypoxanthine-guanine phosphoribosyltransferase (HGPRTase)

Adenine phosphoribosyltransferase (APRTase)

70
Q

APRTase is inhibited by what?

A

Inhibited by AMT

71
Q

HGPRTase is inhibited by what?

A

Inhibited by GMP, IMP

72
Q

There is only one purine NUCLEOTIDE that can be taken up. Which is it?

A

Adenosine by adenosine kinase

73
Q

Which pyrimidine BASE cannot be taken up by humans?

74
Q

Lesch-Nyhan syndrome is the result of a defect in what enzyme? Symptoms?

A

HGPRTase

Symptoms - hyperuriemia, MR, chewing off of fingers

75
Q

Free pyrimidines (not cytosine) are taken up by which enzyme?

A

Pyrimidine phosphoribosyltransferase

76
Q

What enzyme in fungi allows for the use of 5-fluorocytosine as a antifungal medication?

A

Cytosine deaminase

77
Q

Methotrexate is an inhibitor of what enzyme? How does this affect DNA synthesis?

A

Inhibits dihydrofolate reductase, part of the thymidylate synthase reaction. Thus dTMP cannot be produced.

78
Q

Carbamoyl phosphate synthase II is regulated by what?

A

Activated by PRPP

Inhibited by UMP

79
Q

CTP synthase is regulated by what?

A

Activated by UTP

Inhibited by CTP

80
Q

Where does CTP synthase get amine group from?

A

Q to E reaction

81
Q

PRPP synthase is regulated by what?

A

Inhibited by GDP and ADP

82
Q

Amidoribosyltransferase is inhibited by what?

A

GMP and AMP

Enzymes (24 decks)

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