Complex sentence: Protonation of the amine from tryptophan restores aromaticity of the pyridine ring and then imine is hydrolyzed to produce 5-hydroxytryptamine and PLP.
Split into simpler sentences: Protonation of the amine from tryptophan restores aromaticity of the pyridine ring. The imine is hydrolyzed to produce 5-hydroxytryptamine and PLP.