MAOB and Alzheimer disease: Notably, Tryptophan-Tyrosine dipeptide and whey protein hydrolysate GTWY (Gly-Thr-Trp-Tyr) can increase dopamine (DA) content in the hippocampus and frontal cortex of AD mice by inhibiting the activity of monoamine oxidase B (MAO-B) [51,52,53].