---
# System prepended metadata

title: 'Inhibitors, drugs, toxins'
tags: [共筆]

---

# Inhibitors, drugs, toxins
###### tags: `共筆`
## Transcription inhibitor
* **Rifampicin** and **Streptolydigin**
    > RNA polymerase β subunit
* **α-amanitin** (low conc) 
    > RNA polymerase II
* α-amanitin (high conc)
    > RNA polymerase III
* Cordyceptin (3'-deoxyadenosine)
    > Transcription chain terminator
    > both prokaryotesand eukaryotes
* Actinomycin D & Acridine
    > intercalation into DNA between two GC base pairs -> prevents polymerase movement
    > both prokaryotesand eukaryotes
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## Translation inhibitor
* Chloramphenicol
    > Bind to 50s
    > Prevents peptide bond formation
* **Erythromycin**
    > Bind to 50s
    > Prevents translocation
* **Tetracyclines**
    > Binds to 30s
    > Prevents tRNA binding to A site
    > Also works in eukaryotes
* Strepromycin
    > Binds to 30s
    > Alter the structure of 30s
* **Puromycin**
    > Like aminoacyl-tRNA
    > Terminate the protein synthase
    > Also works in eukaryotes
* Cycloheximide
    > Inhibits the translocation activity in the eukaryotic ribosome
* **Diphtheria toxin**
    > Inactivated eEF2 (by ++ADP-ribosylation++ on histone)
## Nucleus receptor targeting drugs
### Agonists
* Pharmacological glucocorticoids 
    > Cortisolm, Triamicinolone, Prednisone, Dexamethasone
    > -> transcription of IκBα -> binds to NF-κB -> ubiquitination
### Antagonists 
* Tamoxifen
    > Breast tumor treatment
    > Binds to estrogen receptors
* RU486
    > Contraceptive agent (避孕藥)
    > Binds to progesterone receptors
## Nicotinic acetylcholine receptor agonists/antagonists
* Sarin
    > Irreversibly inactivating AChE (Acetylcholinesterase) -> 造成ACh過度影響ion channel
    > Causes paralysis
* Tubocurarine
    > Blocks the channel (Receptor antagonist)
## Guanylyl cyclases
* Sildenafil (威爾鋼)
    > Inhibit cGMP phosphodiesterase -> cGMP ↑ -> Longer vasodilation
* Bacterial endotoxin
    > Guanylin -> severe diarrhea.
## G protein
* Cholera toxin (CT)
    > ++ADP-ribosylation++ of Gsα -> GTPase activity inhibited -> Gs locked in an active -> Adenylate cyclase ↑ -> cAMP ↑
* Pertussis toxin (PT)
    > ++ADP-ribosylation++ of Giα -> no GDP-to-GTP nucleotide exchange -> Gi locked in an inactive -> Adenylate cyclase ↑ -> cAMP ↑
## Phosphatidylinositol-derived second messengers
* Phorbol esters
    > Like DAG
    > Tumor promoters