Phenylalanine ammonia-lyase

Phenylalanine ammonia lyase (PAL ) is an enzyme from plants or fungi. PAL converts the amino acid phenylalanine to the release of ammonia ( NH3) to cinnamic acid. This is the first step in the biosynthesis of phenylpropanoids. PAL is one of two enzymes having the amino acid dehydroalanine.

Since phenylalanine is a product of the primary metabolism of the plant and is removed by the formation of cinnamic acid from the primary metabolism, is subject to the biosynthesis of PAL as well as their activity of the control of eg light (via the phytochrome system ) and other factors. The PAL is activated for example when wounding of the plant, likely to stimulate the synthesis of phytochemicals.

The enzyme is usually coded by three or four genes, that is, in many plants, there are several isoforms paralogous.