Amino Acid‐Dependent Host–Guest Interaction: Polyglycerol Dendrimer of Generation 3 Encapsulates Amino Acids Bearing Two Amino Groups

Abstract A polyglycerol dendrimer (PGD), which is known as a biocompatible compound, was demonstrated as a host molecule for amino acids. PGD of generation 3 (PGD‐G3) was found to interact with basic α‐amino acids such as l‐arginine (Arg) and l‐lysine (Lys) in water. The results of isothermal titration calorimetry, ¹H NMR, and ¹H‐¹H NOESY NMR measurements revealed that two basic groups in α‐amino acids were essential for encapsulation by PGD‐G3. An increase in the pK_a value of the amino acid side chains (Arg>Lys>His>Glu) increased the binding constant, thus suggesting that the basicity of α‐amino acids is an important factor to interact with ether oxygen of PGD‐G3. The results demonstrate the utility of PGD‐G3 toward incorporation of α‐amino acids, peptides, and basic proteins in water.