Ligand binding, protein enkephalins

Figure 5.20 Agonists can have different effects on signal activation and internalization. (a) Binding of ligand activates this G-protein-linked receptor, which causes release of the a-subunit. (b) Morphine and etorphine are both agonists of /i- and 5-opioid receptors. The j -axis is an indication of the number of receptors remaining on the plasma membrane. Opioid receptors are rapidly internalized after etorphine treatment (with kinetics similar to internalization after enkephalin treatment), but not after morphine treatment. Adapted from [20].

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