Bifunctional enzyme that catalyzes the decarboxylation of L-phenylalanine to 2-phenylethylamine, which is then oxidized to form 2-phenylacetaldehyde, a constituent of floral scent (PubMed:16766535). 2-phenylacetaldehyde is a precursor of 2-phenylethanol, another constituent of floral scent (PubMed:16766535). H(+) + H2O + L-phenylalanine + O2 = 2-phenylacetaldehyde + CO2 + H2O2 + NH4(+) Optimum pH is 8.5. Homotetramer. Higly expressed in corolla limbs and at lower levels in corolla tubes and ovaries. Follows a circadian-oscillation with the highest expression in the middle of the light phase and the lowest expression in the middle of the dark phase. Flowers of plants silencing PAAS, neither produce 2-phenylacetaldehyde nor 2-phenylethanol. Belongs to the group II decarboxylase family.