Drugs Exam 1

Question 1

methylene blue

Answer 1

a dye that is reduced to leucomethylene blue, which then reduces the ferric iron back to ferrous iron to treat methemoglobinemia

Question 2

anti-inflammatory steroids

Answer 2

inhibit phospholipase A2 to prevent formation of prostaglandins aka eicosanoids by COX.

Question 3

allopurinol

Answer 3

a purine analog used to treat gout (excess uric acid). Purines are carbolized to uric acid (low water solubility), but allopurinol is converted to alloxanthine (AX) by xanthine oxidase (XO). AX competitively inhibits XO, decreasing uric acid and increasing xanthine and hypoxanthine, the mixture of these 3 is more soluble.

Question 4

ciprofloxacin

Answer 4

bacterial topoisomerase II inhibitor

Question 5

nalidixic acid

Answer 5

bacterial topoisomerase II inhibitor

Question 6

etoposide

Answer 6

human topoisomerase II inhibitor

Question 7

doxorubicin

Answer 7

human topoisomerase II inhibitor

Question 8

cytochalasin B and D

Answer 8

fungal toxin that binds to + end of actin filament to block elongation and causing degradation.

Question 9

Phallotoxin (phalloidin)

Answer 9

binds to actin filaments to prevent dissociation into G actin, stabilizes AF; can be used with fluorescent conjugates to label F-actin

Question 10

Cofilin

Answer 10

binds to actin filaments to increase dissociation from - end and stays bound to ADP-actin monomers, preventing reassembly

Question 11

profilin

Answer 11

can stimulate actin exchange of ADP to ATP, so can allow repolymerization

Question 12

Colchicine

Answer 12

bind and inhibit MT polymerization and disrupt MT spindle; stops cell in metaphase

Question 13

colcemid

Answer 13

bind and inhibit MT polymerization and disrupt MT spindle; stops cell in metaphase

Question 14

nocodazole

Answer 14

bind and inhibit MT polymerization and disrupt MT spindle; stops cell in metaphase

Question 15

vincristine

Answer 15

bind to tubulins and inhibit rapidly dividing cells (chemotherapy)

Question 16

vanblastin

Answer 16

bind to tubulins and inhibit rapidly dividing cells (chemotherapy)

Question 17

Paclitaxel/Taxol

Answer 17

stabilizes MT’s and arrests mitosis (chemotherapy)

Question 18

albuterol

Answer 18

relaxes smooth muscle to treat asthma and prevent premature labor

Question 19

Oxytosin

Answer 19

stimulates smooth muscle contraction to induce labor.

Question 20

statins

Answer 20

competitively target HMG-CoA reductase to decrease cholesterol synthesis

Question 21

competitive inhibition

Answer 21

(changes Km, but not Vmax; increasing amount of substrate in constant concentration of inhibitor overcomes effects)

Question 22

sulfanilamide

Answer 22

blocks prokaryotic nucleic acid synthesis through competitive inhibition of dihydropteroate synthetase

Question 23

methotrexate

Answer 23

competitively blocks eukaryotic nucleic acid synthesis through dihydrofolate reductase

Question 24

Captopril

Answer 24

competitively inhibits ACE to treat hypertension

Question 25

Coumadin

Answer 25

mimics vitamin K to competitively inhibit γ-glutamyl-carbocylase reaction in the hepatic synthesis of coagulation factors; blood thinner.

Question 26

cyanide and sulfide

Answer 26

suicide inhibitors of the ETC

Question 27

organophosphates

Answer 27

suicide inhibitors (like serine nerve gas inhibiting acetylcholinesterase)

Question 28

aspirin

Answer 28

suicide inhibitor for COX; through inactivation of PGH synthase by addition of an acyl group to Ser 530 in active site? Irreversibly interferes with prostaglandin synthesis

Question 29

5-bromouracil

Answer 29

Base analog that is incorporated into DNA and causes mutations

Question 30

N-methyl-N-nitrosoguanidine (MNNG)

Answer 30

Alkylating agent (attaches alkyl group)

Question 31

nitrous acid

Answer 31

Deaminating agent removes amino group: Deamination of A results in hypoxanthine, G results in xanthine, and C results in deoxyuracil

Question 32

ethidium bromide

Answer 32

intercalating agents insert between stacked bases to cause frameshift mutations

Question 33

proflavin

Answer 33

intercalating agents insert between stacked bases to cause frameshift mutations

Question 34

Rifampicin

Answer 34

specifically inhibits RNA initiation in prokaryotes by binding to beta subunit of bacterial RNA pol; does not inhabit eukaryotic RNA pol

Question 35

α-amanitin

Answer 35

toxic mushroom poison from the “death cap” mushroom that binds very tightly to eukaryotic RNA pol II and prevent formation of mRNA through elongation; no effect on bacterial RNA pol

Question 36

Actinomycin D

Answer 36

binds to dsDNA at deoxyguanosine residues through intercalating into the helix. Specifically inhibits RNA synthesis, but not replication or protein synthesis; works by inhibiting the formation of a transcription bubble, thereby inhibiting RNA elongation. This is not specific for prokaryotes or eukaryotes

Question 37

Streptomycin

Answer 37

Causes misreading of the genetic code. (Prokaryotes) Interferes with initiation by binding to the small subunit and preventing assemebly of the small and large subunits

Question 38

Tetracycline

Answer 38

Inhibits binding of aminoacyl-tRNA to the A-site: Prokaryotic antibiotic

Question 39

Choramphenicol

Answer 39

Inhibits peptidyl transferase activity on ribosomes: Prokaryotic antibiotic

Question 40

Erythromycin

Answer 40

Binds to the 50S subunit and inhibits translocation: Prokaryotic antibiotic

Question 41

Puromycin

Answer 41

Resembles aminoacyl-tRNA and binds to A-site. Causes premature release of polypeptide chain. (Prokaryotic & eukaryotic)

Question 42

Cycloheximide

Answer 42

Inhibits translocation during elongation: eukaryotic

Question 43

Diphtheria toxin

Answer 43

Inhibits eEF-2 and prevents translocation: eukaryotic

Question 44

Ricin

Answer 44

Inactivates 60S subunit of ribosome: eukaryotic

Question 45

Pertussis toxin

Answer 45

Causes pertussis aka whooping cough. Toxin is endocytosed and ribosylates the αi subunit (inhibitory subunit) resulting in the protein being locked in the GDP bound state, resulting in increased cAMP