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Step 1 2019 First Aid Flashcards > Enzymes > Flashcards

Enzymes Flashcards

1
Q

Reversibly inhibits IMP dehydrogenase

A

Mycophenolate Mofetil

Ribavirin

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2
Q

inhibits dihydroorotate
dehydrogenase

A

Leflunomide

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3
Q

inhibit dihydrofolate
reductase

A

Methotrexate (MTX), trimethoprim (TMP),
and pyrimethamine:

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4
Q

inhibits
thymidylate synthase

A

5-fl orouracil (5-FU) and its prodrug
capecitabine: form 5-F-dUMP, which inhibits
thymidylate synthase

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5
Q

inhibit inosine
monophosphate dehydrogenase - use?

A

Mycophenolate - used for lupus nephritis

Ribavirin - Hep C

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6
Q

inhibits ribonucleotide
reductase - use? SE/

A

Hydroxyurea

Use - SCD, Myeloproliferative disorders (PCV, CML)

SE - megaloblastic anemia,

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7
Q

Location and use of CPS I v CPS II

A

CPS 1 - mitochondria
CO2 + NH3 + ATP –> Carbamoyl PO4
Urea cycle 1st step

CPS 2 - cytosol
Glutamine + CO2 + ATP –> Carbamoyl PO4 in pyrimidine base production

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8
Q

Adenosine Deaminase def - Dz, MoI?

A

SCID - AR

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9
Q

HGPRT def

A

Lesch Nyhan -

Hyperuricemia Gout Pissed off (aggression, self-mutilation) Retardation (intellectual disability) DysTonia

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10
Q

DNA Helicase

A

Bloom Syndrome

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11
Q

inhibits RNA polymerase II. Causes severe hepatotoxicity if ingested

A

α-amanitin, found in Amanita phalloides (death cap mushrooms

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12
Q

inhibits RNA polymerase in both prokaryotes and eukaryotes.

A

Actinomycin D,

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13
Q

inhibits DNA-dependent RNA polymerase in prokaryotes.

A

Rifampin

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14
Q

N-acetylglucosaminyl-1-phosphotransferase

A

I-cell disease (inclusion cell disease/mucolipidosis type II)—inherited lysosomal storage disorder

coarse facial features, gingival hyperplasia, clouded corneas, restricted joint movements, claw hand deformities, kyphoscoliosis, and high plasma levels of lysosomal enzymes. O

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15
Q

myotonin protein kinase

A

Myotonic dystrophy

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16
Q

Cofactor of transketolase, which pathway?

A

B1

HMP shunt

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17
Q

Cofactor in ALT/AST

A

B6

Why alcoholics may not have inc LFTs

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18
Q

3 rxns that need B7 as cofactor

A

ƒƒ Pyruvate carboxylase: pyruvate (3C)
–> oxaloacetate (4C)
ƒƒ Acetyl-CoA carboxylase: acetyl-CoA (2C)
–> malonyl-CoA (3C)
ƒƒ Propionyl-CoA carboxylase: propionyl-CoA
(3C) –> methylmalonyl-CoA (4C)

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19
Q

cofactor for dopamine
β-hydroxylase

A

Vitamin C

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20
Q

(+)’d by epoxide reductase

A

Vitamin K

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21
Q

(-) alcohol DH

A

Fomepizole

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22
Q

blocks acetaldehyde dehydrogenase

A

Disulfiram

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23
Q

Neurologic defects, lactic acidosis, inc serum alanine starting in infancy

A

Pyr DH complex def

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24
Q

most common human enzyme deficiency

A

G6PD def

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25
Q

MoI of G6PD def

A

XLR

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26
Q

fructokinase sx

A

fructose appears in blood and urine.

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27
Q

hypoglycemia, jaundice, cirrhosis, vomiting.

A

aldolase B

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28
Q

isolated infantile cataracts.

A

galactokinase def

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29
Q

galactose-1-phosphate uridyltransferase

A

Damage is caused by accumulation of toxic substances (including galactitol, which accumulates in the lens of the eye).

Symptoms develop when infant begins feeding (lactose present in breast milk and routine formula) and include failure to thrive, jaundice, hepatomegaly, infantile cataracts, intellectual disability

+ kidney sx - amino aciduria, hyperchloremic metabolic acidosis

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30
Q

aldose reductase located where?

A

Lens has primarily aldose reductase. Retina, Kidneys, and Schwann cells have only aldose reductase

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31
Q

Which organs have both aldose reductase and sorbitol DH?

A

Liver, Ovaries, seminal vesicles

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32
Q

Cofactor for aldose reductase / sorbitol DH?

A

a) NADPH
b) NAD+

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33
Q

Ornithine transcarbamylase deficiency - MoI, sx

A

inc orotic acid in blood and urine, dec BUN, symptoms of hyperammonemia

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34
Q

Homogentisate oxidase

A

Alkaptonuria

Autosomal recessive. Usually benign.
Findings: bluish-black connective tissue, ear cartilage, and sclerae (ochronosis); urine turns black on prolonged exposure to air. May have debilitating arthralgias (homogentisic acid toxic to cartilage).

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35
Q

Tyrosinase

A

Albinism

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36
Q

Phenylalanine hydroxylase

A

PKU

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37
Q

branched-chain α-ketoacid dehydrogenase

A

Maple syrup urine disease

vomiting, poor feeding, urine smells like maple syrup/burnt sugar. Causes severe CNS defects, intellectual disability, death.

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38
Q

propionylCoA carboxylase - sx?

A

Propionic acidemia

poor feeding, vomiting, hypotonia, anion gap metabolic acidosis, hepatomegaly, seizures.

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39
Q

Glucose 6 Phosphatase - sx?

A

Von Gierke

Severe fasting hypoglycemia, –> inc Glycogen in liver and kidneys, inc blood lactate, triglycerides, uric acid (Gout), and hepatomegaly, renomegaly.

amino acid competes for same transporter as glucose, hence the inc in uric acid.

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40
Q

Lysosomal acid α-1,4glucosidase - dz?

A

Pompe

Cardiomegaly, hypertrophic cardiomyopathy, hypotonia, exercise intolerance

41
Q

α-1,6-glucosidase

A

Cori disease (type III)

42
Q

Skeletal muscle glycogen phosphorylase

A

McArdle disease (type V)

43
Q

HeXosaminidase A

A

Tay-Sachs disease

44
Q

α-galactosidase A

A

Fabry disease

45
Q

Arylsulfatase A

A

Metachromatic leukodystrophy

46
Q

Galactocerebrosidase (galactosylceramidase)

A

Krabbe disease

47
Q

Glucocerebrosidase (β-glucosidase)

A

Gaucher disease

48
Q

Sphingomyelinase

A

Niemann Pick disease

49
Q

α-l-iduronidase

A

Hurler

50
Q

Iduronate-2-sulfatase

A

Hunter syndrome

51
Q

Medium-chain acyl-CoA dehydrogenase deficiency

A

— ability to break down fatty acids into acetyl-CoA –> accumulation of fatty acyl carnitines in the blood with hypoketotic hypoglycemia. Causes vomiting, lethargy, seizures, coma, liver dysfunction, hyperammonemia.

52
Q

HMG-CoA synthase and lyase

A

ketone production

53
Q

HMG-CoA reductase

A

chol synthesis

54
Q

Lipoprotein lipase Cofactor

A

C-II

55
Q

Activates LCAT

A

A-I

56
Q

Hepatic lipase

A

Degrades TGs remaining in IDL

57
Q

Hormone-sensitive lipase

A

Degrades TGs stored in adipocytes.

58
Q

PCSK9 fxn?

drug that targets it?

A

degrades LDL receptor

Alirocumab,
evolocumab

59
Q

Lipoprotein lipase or apolipoprotein C-II deficiency - sx?

A

Type I dyslipidemia - Hyperchylomicronemia

Pancreatitis, hepatosplenomegaly, and eruptive/pruritic xanthomas

60
Q

Defect of NADPH oxidase

how to test for it?

A

Chronic granulomatous disease

Abnormal dihydrorhodamine (flow cytometry) test ( dec green fluorescence).
Nitroblue tetrazolium dye reduction test (obsolete) fails to turn blue.

no blue, no green for CGD

61
Q

reversibly (-) IMP DH - use? SE/

A

Mycophenolate
Mofetil
use - lupus nephritis

SE/ GI upset, pancytopenia,hypertension,
hyperglycemia.
Associated with invasive CMV infection.

62
Q

Urease + organisms

predisposes you to what type of stones

A

Proteus, Cryptococcus, H pylori, Ureaplasma,
Nocardia, Klebsiella, S epidermidis,
S saprophyticus.

struvite stones (ammonium magnesium phosphate)

63
Q

Patients with NADPH def have susceptibility to ________ positive organisms

List them

A

Catalase +

G+ = Nocardia, Listeria, Staphylococci,

G- = Pseudomonas, E coli,
Serratia, B cepacia, H pylori.

Fungi = Aspergillus, Candida,

64
Q

IgA protease secreted by ?

A

S pneumoniae, H influenzae type b, and Neisseria (SHiN).

65
Q

Adding deoxyribonuclease degrades naked
DNA, preventing ______ (this bacterial process)

A

Transformation

66
Q

List 3 bacterial toxins that overactivate adenylate cyclase

A 
ETEC heat labile toxin
Cholera toxin (by (-) Gi)
Bordetella pertussis (disable Gi)
67
Q

Bact toxin that mimics adenylate cyclase

A

Bacillus anthracis

68
Q

In an AB toxin, the active a component is usually

an ___ _________

A

ADP ribosyltransferases

69
Q

bacterial toxin that is a lecithinase/phopholipase

A

Clostridium perfringens alpha toxin

70
Q

Which staphylococci are coagulase + vs -

A

+ = S. aureus

  • = S. saprophyticus, S. epidermidis
71
Q

Which G- diplococci produces maltose acid?

A

N. meningiditis
N. gon and Moraxella are neg for maltose acide

72
Q

Which G- bacilli ferment lactose

A

Fast - E. coli, Klebsiella, Enterobacter
Slow - Citrobacter, Serratia

73
Q

Of the bacilli non lactose fermenters, which

produces oxidase

A

Pseudomonas

74
Q

Which G- bact produce Phospholipase C

A

Pseudomonas - breaks down cell membranes

75
Q

Which microorganism leads to (-)’n of tyrosinase?

A

Tinea versicolor (hypo/hyperpigmentation)

Malassezia furfur

76
Q

Naked nucleic acids of ⊝ strand ssRNA and dsRNA viruses are not infectious. They require ________contained in the complete virion.

A

polymerases

77
Q

DNA virus with its own reverse transcriptase

A

Hepadna (Hep B)

78
Q

-ssRNA virus that produces neuraminidase

A

Influenza (Orthomyxo)

Parainfluenza (Paramyxo) - croup

79
Q

Antibiotics that binds transpeptidases

A

All Beta lactams - bind penicillin binding proteins (transpeptidases)

80
Q

inhibitor of renal dehydropeptidase I, given with carbapenems

A

Cilastatin

81
Q

Rx that Inhibit dihydropteroate synthase

A

Sulfonamides, Dapsone

82
Q

Inhibit prokaryotic enzymes topoisomerase
II (DNA gyrase) and topoisomerase IV.

A

Flouroquinolones

83
Q

Inhibit DNA-dependent RNA polymerase.

A

Rifampin, Rifabutin

84
Q

Rx that dec carbohydrate polymerization of mycobacterium cell wall blocking arabinosyltransferase.

A

Ethambutol

85
Q

Inhibits DNA and RNA biosynthesis by conversion to 5-fluorouracil by cytosine deaminase.

A

Flucytosine

86
Q

Inhibits the fungal enzyme squalene epoxidase.

A

Terbinafin

87
Q

Inhibit influenza neuraminidase

A

Oseltamivir, Zanamivir

88
Q

Acyclovir, etc are monophosphorylated by ?

A

Monophosphorylated by HSV/VZV thymidine kinase and not phosphorylated
in uninfected cells –> few adverse effects.

89
Q

Viral DNA/RNA polymerase inhibitor and
HIV reverse transcriptase inhibitor.

A

Foscarnet

90
Q

inhibits viral DNA polymerase

A

Ganciclovir and Cidofovir

91
Q

Pyruvate DH def leads to an increase of what in the blood?

A

lactic acid

serum alanine

92
Q

Sofosbuvir and Dasabuvir work on what enzyme?

A

Inhibits NS5B, an RNA-dependent RNA
polymerase

93
Q

Grazoprevir ,Simeprevir (-) what enzyme

A

Inhibits NS3/4A, a viral protease, preventing
viral replication.

94
Q

Enzyme in the 3rd phase of wound healing - needs ______ to function

A

Collagenases - break down type III collagen, need zinc to function

95
Q

Granulomas are associated with hypercalcemia bc of ?

A

Inc 1alpha hydroxylase mediate vitamin D activation in macrophages

96
Q

In invasive carcinomas, cells have invaded basement membrane using

A

using collagenases and hydrolases (metalloproteinases)

cell-cell contacts lost by inactivation of E-cadherin

97
Q

regenerates AchE

A

pralidoxime

98
Q

Phentolamine is used to patients on _______ ______ who eat meat and cheese

A

MAO inhibitors

99
Q
A

Step 1 2019 First Aid Flashcards (63 decks)

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