INS and type 2 diabetes mellitus: The decay of phenylalaninemetabolism and phenylalanine, tyrosine, and tryptophan biosynthesisthe in T2D model could be attributed to the increased amino acid utilizationfor gluconeogenesis as a result of the impaired β-cell capacityto produce insulin and/or the compromised insulin signaling.58 H-AAPP and H-NAAB might improve insulin signalingby regulating phenylalanine, tyrosine, and tryptophan biosynthesisand phenylalanine metabolism at week 4.