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Flashcards in Receptor Theory Deck (16)
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1

Name the four receptor types

1. receptors
2.Enzymes
3.Transport/carriers
4.Ion channels

2

Where would you find receptors and what binds to them

Proteins found on the plasma membrane or intracellularly that recognise and respond to an endogenous ligand

3

What is a small molecule

Molecules that come in tablet form

4

What is a biological

A peptide that has been engineered to interact with drug binding proteins

5

What are the four receptor families and their characteristics

1. Ligand gated ion channel - 4TMDs - Extracellular ligand binding site on the N-terminus
2.GPCR - 7TMDS - Ligand binding sites can be outside (peptides) or inside a pocket created by the transmembrane domains (Small molecules) - Signalling is transduced by G proteins - Alpha subunit exchanges its GDP for GTP and dissociates from the beta and gamma subunits - this causes signal transduction - turned off with dephosphorylation - subunits come back together
3. Kinase linked receptor - 1TMD - All kinase linked ligands are peptides - Binding site on outside of the cell on the amino terminus - kinase domains phosphorylate proteins
4. Nuclear receptor - No TMDs - Found within the cytosol - DNA binding domain - control of transcription

6

What are the units of affinity

Molarity (M)

7

What does affinity describe

How well the drug will physically and chemically interact with the receptor

8

How is affinity measured

As a ratio of the forward and backward binding reactions

9

What is Ka

k+1/k-1

10

What is Kd

k-1/k+1

11

How is high affinity achieved in terms of Ka and Kd

If Ka is high and Kd is low then affinity will be high

12

What does it mean to have low Kd

The molecules are more likely to remain together

13

What is efficacy

The likeliness of a drug receptor complex to illicit a response in the cell

14

How is efficacy measured

1-0

15

What is occupancy

Total number of receptors occupied/Total number of receptors

16

How is occupancy measured

1-0