Figure 1: 2-PE metabolic pathways. On the top, the plant metabolic pathway with two enzymatic steps is presented: the first step is the conversion of L-phe into phenylacetaldehyde by PAAS with PLP as the cofactor. The second step is the conversion of phenylacetaldehyde to 2-PE by adehydrogenase. On the bottom, the Ehrlich pathway abundant in yeast is shown including three well-described enzymatic steps. The scheme is based on the suggestions of Achmon et al. [1].