Week 4 Flashcards
What is specificity?
can bind to only one specific receptor
G-coupled protein receptor
Ion channel opening is responsible to
Acetylcholine binds to muscarinic receptor (an example)
acetylcholine binds to more than one receptor-giving two diff effects
7 transmembrane
Ligand gated ion channel
Ion usually moves down the concentration gradient.
Resting potential is negative
Ligand/drug binds to receptor and transduction mechanism(change in protein structure that) allows the channel to open
4 transmembrane
pentametric structure
Kinase linked receptor
Adds a phosphate, gene transcription, protein synthesis, cellular effects
1 transmembrane
Nuclear receptor
Agonist doesn’t bind to recognition site/receptor, the receptor is inside the cell (nucleus)/cytoplasm and then moved to nucleus
In order for agonist to bind to the receptor it has to pass through membrane
Cell membrane is hydrophobic therefore a polar molecule has to pass through
0 transmembrane and binding in in c terminal
G-protein function
G-protein-subunits- alpha beta and gamma
Step 1: receptor non stimulated the subunits are embedded into cell membrane and bind to GDP
Step 2. when ligand bind. Conformation change-receptor changes shape and we can alter how the ligand sits on receptor
And GDP in alpha subunit is converted to GTP
Step 3: GTP moves near target site , target protein is activated by dissociation of alpha unit
Target inactivate by converting GTP into GDP/ autoregulating
Alpha unit associate with betta and gamma subunit
Different flavours og g-protein
Gs protein, alpha sub unit, agonist bind to receptor and increase activity of target enzyme.
With inhibitory receptor using gi alpha sub unit will turn down activity of target enzyme.
A bit of agonist stimulating both ways, we can have a balance of activity.
Why do you think a second messenger system is a good thing?
Provides a site for a potential drug action-
Allows for amplification of response
