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Flashcards in Tough ones Deck (82):
1

Where does Q get it's ammonium from?

NH4

2

What is the role of ALT in starvation?

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

3

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

From Q

4

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

Serine-hydroxymethyl transferase

5

What is the most oxidized form of THF?

N10

6

What is the most reduced form of THF?

N5

7

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

Formaldehyde, formate, S, G, H

8

What is the cause and symptoms of Homocystieneuria?

Defect in Cystathinoine beta synthase
Lens dislocation, MR, thromboembolism

9

What are the symptoms of PKU? Treatment?

MR, SZs, rash

Low F and Y diet

10

Which amino acids serve as carbon donors in the blood?

A and Q

11

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

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

12

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

Glycine encephalopathy

13

Biotin is needed for what reaction?

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

14

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

Propionyl to succinyl-coa reaction

Homocystine to methionine reaction

15

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

THF

16

What is the chemical responsible for he discoloration of alkaptonuria?

Benzoquinone

17

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

Succinyl acetone

18

Which amino acids can undergo deamination without an aminotransferase?

THCS

19

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

Q, then citrulline, then R

20

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

Phenyl-butryrate reactions with glutamine
Benzoate reacts with glycine

21

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

Pryidoxal phosphate

22

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

PPRE

23

Gluconeogenesis stimulate transription of enzymes through what?

CRE

24

Insulin induces transcription of lipid synthesis enzymes via what?

SRE

25

Insulin represses transcription of gluconeogenesis enzymes via what?

IRE

26

The enzyme IDO converts what to what in which pathway?

W to N-formylynurine in the synthesis of niacin

27

How does the enzyme IDO contribute to cancer?

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

28

A defect in carbomoyl synthetase I leads to what condition?

Hyperammonemia

29

A defect in Ornathine transcarbamoylase leads to what condition?

Hyperammonemia

30

A defect in arginosuccinate synthetase leads to what condition?

Citrullinemia

31

A defect in Arginosuccinate lyase leads to what condition?

Arginosuccinate acid uria

32

A defect in Arginase leads to what condition?

Hyperarginemia

33

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

Glutathione s-transferases

34

What are three symptoms common to DM patients?

Fasting hypoglycemia
Hyperlipidemia
Gluconeogenesis from muscles

35

Why is there hyperlipidemia in DM patients?

Insulin is either ineffective at inhibiting HSL or not present.

36

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

Increases in FA synthetase
Decrease in PEP carboxykinase

37

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

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

38

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

UPG III decarboxylase.
Photosensitivity, pink urine

39

What enzymes in the heme cycle does Pb inhibit?

ALA synthase and Ferrochelatase

40

What gives urine and stool their characteristic color?

Urobilin

41

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

Elevated unconjugated bili in blood
No change in urine or stool

42

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

Increase is unconjugated bili in the blood
Lower amount of bili in urine and stool

43

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

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

44

PRPP is synthesized from what substrate and via which enzyme?

RIbose-5-phosphate
PRPP synthase

45

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

Amidoribosyltransferase
PRA

46

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

Amino acids (GED)
CO2
N10 formyl THF
ATP

47

What is required for AMP synthesis? For GMP?

GTP and ATP respectively.

48

AMP and GMP are phosphorylated by what enzymes?

nucleotide mono(di)phosphate kinases

49

PRPP synthetase in inhibited by what?

ADP and GDP

50

What are the inhibitors and activators of Amidoribosyl transferase?

Inhibitors = GMP, AMP,
Activator = PRPP

51

Why does EtOH consumption worsen symptoms of gout?

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

52

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

Allopurinol
Oxypurinol

53

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

UMP synthase

54

UMP synthase is a combination of which two enzymes?

Oratate phosphoribosyl transferase and OMP decarboxylase

55

CAD is a combination of which three enzymes?

Carbamoyl phophate sythetase
Aspartate transcarbamoylase
Dihydroorotase

56

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

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

Hydroxyurea blocks which reaction?

Ribonucleotide reductase

58

Deoxyribonucleotides are producted via which enzyme?

Ribonucleotide reductase

59

Ribonucleotide reductase requires what molecule to reduce ribonucleotide?

Thioredoxin

60

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

Thioredoxin reductase.
NADPH

61

Which dNTP regulates all dNTP production

dATP

62

How is CTP generated?

From UTP via CTP synthase

63

SCID is a defect in what enzyme?

Adenosine deamiase

64

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

SCID

65

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

FALSE

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

66

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

FUMP, FdUMP, and irreversibly binds Thymidylate synthase

67

Beta-alanine is produced from what?

Degradation of the pyrimidines UMP, CMP, and dCMP

68

Betaisobutryate is produced from what?

Degradation of the pyrimidine dTMP

(used as a measure of DNA turnover)

69

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

Hypoxanthine-guanine phosphoribosyltransferase (HGPRTase)

Adenine phosphoribosyltransferase (APRTase)

70

APRTase is inhibited by what?

Inhibited by AMT

71

HGPRTase is inhibited by what?

Inhibited by GMP, IMP

72

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

Adenosine by adenosine kinase

73

Which pyrimidine BASE cannot be taken up by humans?

Cytosine

74

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

HGPRTase
Symptoms - hyperuriemia, MR, chewing off of fingers

75

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

Pyrimidine phosphoribosyltransferase

76

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

Cytosine deaminase

77

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

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

78

Carbamoyl phosphate synthase II is regulated by what?

Activated by PRPP
Inhibited by UMP

79

CTP synthase is regulated by what?

Activated by UTP
Inhibited by CTP

80

Where does CTP synthase get amine group from?

Q to E reaction

81

PRPP synthase is regulated by what?

Inhibited by GDP and ADP

82

Amidoribosyltransferase is inhibited by what?

GMP and AMP