Receptor Families Flashcards
Define drug affinity?
How attracted a drug is to its receptors
Define drug efficacy?
A drug’s ability to activate the receptor once it has bound. How good a drug is at producing the desired effect.
Order of potency for alpha receptor?
Noradrenaline>adrenaline>isoprenaline
Order of potency for beta receptor?
Isoprenaline>adrenaline>Noradrenaline
Effect of a1 on downstream cascades?
+ IP3
Effect of a2 on downstream cascades?
-cAMP
Effect of b1 on downstream cascades?
+cAMP
Effect of b2 on downstream cascades?
+cAMP
What does gene cloning lead to?
Identification of distinct subtypes not realised by pharmacological classification
What is cDNA screening?
Purify the receptor protein and get a partial amino acid sequence.
Oligonucleotides to mimic the DNA sequence predicted.
Locate cDNA -> full receptor sequence
Found 2 different receptors.
Homology screening?
cDNA with low stringency, find homologous, novel receptors.
Found 10 different receptors.
ESTs and data mining?
cDNA derived from the tissue mRNA predicts te protein.
EST is a small piece of DNA sequence which can be found in the database.
Similar –> homologous
Found 100 different receptors
Genome sequencing?
Computer annotated. Compare new genes with known receptors and make a splicing prediction based on the genome sequence.
Found 1000s of different receptors.
How do receptors get identified as relatives of one family?
Sequence comparison, established function and protein prediction.
What can be predicted from amino acid sequences?
transmembrane domains - hydrophobic amino aicds
