BIOCHEM 2EE3 Lecture Notes - Lecture 13: Skeletal Muscle, Peptide, Lidocaine
6 Mar 2014
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Biochemistry 2ee3 lecture 13: channel allows passive transport, pumps allow active transport, use a lot of atp to transport against concentration gradient, carrier: hydrophobic exterior, hydrophilic binding site which diffuse through membrane called ionosmall molecules. Ligand gated ion channel, acetylcholine is ligand: does not allow anions through, acetylcholine receptor depolarizes membrane in skeletal muscle activates membrane potentials. Ligand is called agonist because it activates channel to open it. If channel malfunctions, death of organism: prevents functioning of nicotinic acetylcholine receptor, no more nerve impulses because depolarization blocked. Targets extracellular vestibule of channel: does not target all types of nicotinic acetylcholine receptor, only skeletal muscle, affect is paralysis. 3 positively charged residues: lys, arg, : voltage gated open up to depolarization, when membrane depolarizes, gate opens, channels are selective, any ion channels (~400 types of them) are often targets for drugs/toxins. Tetreodotoxin blocks na channel: express toxin due to what they eat, do not synthesize it.
