Exploring the biological consequences of conformational changes in aspartame models containing constrained analogues of phenylalanine

The dipeptide aspartame (Asp-Phe-OMe) is a sweetener widely used in replacement of sucrose by food industry. 2 ',6 '-Dimethyltyrosine (DMT) and 2 ',6 '-dimethylphenylalanine (DMP) are two synthetic phenylalanine-constrained analogues, with a limited freedom in chi-space due to the presence of methyl groups in position 2 ',6 ' of the aromatic ring. These residues have shown to increase the activity of opioid peptides, such as endomorphins improving the binding to the opioid receptors. In this work, DMT and DMP have been synthesized following a diketopiperazine-mediated route and the corresponding aspartame derivatives (Asp-DMT-OMe and Asp-DMP-OMe) have been evaluated in vivo and in silico for their activity as synthetic sweeteners.