Chapter 4

There are two main types of adrenergic receptor: the \(\alpha\) and \(\beta\)-adrenoceptors. Noradrenaline shows slight selectivity for the \(\alpha\)-receptor, whereas isoprenaline shows selectivity for the \(\beta\)-adrenoceptor. Adrenaline shows no selectivity and binds equally well to both the \(\alpha\)-and \(\beta\)-adrenoceptors. Suggest an explanation for these differences in selectivity.

Suggest why the transmembrane regions of many membrane-bound proteins are \(\alpha\)-helices.