“A 30 ….1 mM CuCl2 suppressed responses to single … sweeteners: L-alanine, L-proline , D-tryptophan, 6-chloro-D-tryptophan, L-valine, glycine, sucrose, maltose, lactose, tetrachloro-galacto-sucrose, glucose, fructose, methyl …, sorbitol, sodium saccharin, L-4'-cyano-3'-(2-2-2-trifluoro acetamido)succinanilic acid, phenethyurea, and stevioside.”