Dietz Flashcards
Phase I metabolism is usually catalyzed by what enzyme?
CYP450
T/F Your metabolite gets higher water solubility (become more hydrophilic) after amino acid conjugation.
F
Glucuronidation formula
R-OH + sugar –> R-O-sugar
Sulfate conjugation formula
ROH + SO4 (-2) —–> R-O-SO3-
Glutathione conjugation formula
RX + GSH —> R-S-G
Glucuronidation substrates
Phenols, 1 alcohol, 2 alcohol, 3 alcohol, aromatic amines, acids
Sulfate conjucation substrates
Phenols, alcohols, aromatic amines
Is GSH nucleophile or electrophile?
Nucleophile. Becomes GS- and helps get rid of electrophiles
Most conjucation of glucuronidation are active or inactive? What’s an exception?
Most are inactive except for morphine-6-glucuronide
Reactions of glucuronic conjugation? What does it conjugate with?
Bilirubin, drugs, pesticides, carcinogens
What kind of conjugation does Zileuton have? And what does it form?
UTG conjugation (glucuronidation) and it’ll form N-O-glucuronide
What’s the Crigler-Najjar syndrome?
Jaundice. Mutated UGT1A1 resulting in the inability for the UGT to perform glucuronidation. A bunch of unconjugated bilirubin left, causing toxicity.
What’s Gilbert’s syndrome?
When the UGT1A1 enzyme is off resulting in UGT not able to glucuronize bilirubin causing an excess of it in the body, thus jaundice.
What’s Gray Baby syndrome?
When neonates don’t have enough UGT yet and fails to conjugate chloramphenicol, leading to vasomotor collapse and cell toxicity.
What is UGT1A1*28? What does it cause?
It’s a varient that causes less expression of UGT1A1, leading to unconjugated hyperbilirubinemia and decreased drug clearance leading to toxicity ex. irinotecan
What can lead to too much SN38?
When there’s a lack of expression of UGT1A1 and the SN38 (which came from prodrug irinotecan) can’t be conjugated into an inactive form and will just keep accumulating.
Why do some glucuronides have long half lives?
Some may re-enter the intestine and reabsorbed again, deconjugated by B-glucuronidase in the colon, making the half life longer.
What’s PAPS? Is it an electrophile or nucleophile?
Co-factor for sulfate conjugation. Electrophile.
What are sulfate conjugation substrates?
Phenols (most common), alcohols, aromatic amines, N-hydroxls
How does metabolism through sulfate conjugation alter rate of renal clearance of a drug?
It makes the drug a lot more hydrophilic and water soluble by adding that SO3-
What is Phenacitin? How excreted?
Pain/fever reliever. Can be excreted through sulfate conjugation.
How to get estrogenic activity?
By having enzyme sulfatase remove the sulfate on the conjugated estrogen and make it active again.
How is DMBA activated?
DMBA will go through sulfate conjugation and after that the sulfate group will leave through SN1, making the DMBA a carbocation, which is super reactive and can cause carcinogen. It can be detoxified by GSH.
What does glutathione conjugation try to do? (eliminate what?) And what groups does it target? Name 4.
Gets rid of electrophiles
Epoxides, alkyl halides, AB-unsaturated carbonyls quinones
What’s a Michael receptor?
It’s an AB-unsaturated carbonyl and is an electrophile which can be attacked by the nucelophile GSH.
Explain Aflatoxin detoxification.
Basically aflatoxin can become a toxic bitch by forming an epoxide after being metabolized by P450. Then GSH comes in like a mofo hero ass (with the help of GST) and attack the shiz outta that electrophile and walla DETOX.
Name a drug that can go through N-acetyltransferase and name the co-factor that it needs
Procainamide, it needs acetyl-CoA