Receptors 1 Flashcards
what is a receptor?
the term denotes the component of the organism with which the chemical agent is presumed to interact
what is the majority of drug target?
receptors are the majority of drug targets
what are the majority of receptors?
proteins 24% enzymes 9% voltage gated ion channels 8% membrane transporters 12% other
how would you describe the primary structure of a protein?
the amino acid sequence of the polypeptide chain
how is a peptide bond formed between two amino acids?
through a condensation reaction
what are the secondary structures of protein?
alpha helix and beta pleated sheet
what is the tertiary structure of proteins?
Three-dimensional structure of a peptide, results from hydrophobic and hydrophilic interactions between residues far apart on the chain. Disulfide bonds and hydrogen bonds can also add to the tertiary structure of the protein.
What is the quatenary structure of a protein?
consists of two or more polypeptide chains or subunits. “Higher order of peptide come together to form multi subunit”
what is β2AR-Gs?
gene protein
What is β2AR-Nb80?
antibody
What is the β-adrenergic receptor?
it is a protein
intracellular receptors
receptors located inside the cell rather than on its cell membrane ex: Steroid R
receptor tyrosine kinases
membrane receptors that attach phosphates to tyrosines Ex: Growth Factor R
Ligand-gated Ion Channels
Ion channels that respond to chemical signals rather than to the changes in membrane potential generated by ionic gradients. The term covers a large group of neurotransmitter receptors that combine receptor and ion channel functions into a single molecule. The signal binds to and directly regulates the opening of an ion channel Ex: Nicotinic AChR
G protein-coupled Receptors
the signal binds to a cell-surface receptor linked to an effector enzyme by a G protein. Ex: Adrenergic R, Muscarinic AChR
what is the mechanism of α-Bungarotoxin neurotoxin?
it binds to nicotinic AChR tenaciously and blocks the receptor.
What happens if someone is exposed to snake venom with the α-Bungarotoxin neurotoxin?
paralysis aka lack of muscle contraction
What is the mechanism of Epibatidine?
it binds to nicotinic AChR very tightly and activates the receptor
What will happen if someone is exposed to the toxin Epibatidine?
They would experience uncontrollable movement, contractions and eventually paralysis
What do cell membranes potentials result from?
- Uneven distribution of ions across the membrane
- selective permeability of different ions
At resting potential what is there a lot more of? how much?
there are about ten times more open K+ channels than open Na+ and Cl- channels
What is the consequence of more K+ channels being open?
more positively K+ ions exit the cell. than Na+ and Cl- ions enter, and the outside plasma membrane acquires a net positive charge relative to the inside.
What leads to depolarization?
opening of nAChR leads to influx of sodium ions
what happens when the membrane potential depolarizes above a threshold level?
voltage-sensitive Na+ channels are triggered to open causing more Na+ influx which initiate the action potential
