Phenylalaninammoniaklyase

Phenylalaninammoniaklyase, often abbreviated as PAL, is an enzyme that catalyzes the non-oxidative deamination of L-phenylalanine to cinnamic acid and ammonia. This reaction is a crucial step in the biosynthesis of phenylpropanoids, a large class of plant secondary metabolites. These compounds play vital roles in plant defense, growth, and development, and include important molecules such as flavonoids, lignans, and lignin.

PAL is found in plants, fungi, bacteria, and archaea. In plants, its activity is highly regulated and often induced by various stimuli, including mechanical wounding, pathogen attack, UV radiation, and developmental signals. This regulation allows plants to rapidly produce phenylpropanoids in response to environmental stress or specific needs. The enzyme belongs to the lyase family and requires pyridoxal phosphate (PLP) as a cofactor.

The discovery and characterization of PAL have been instrumental in understanding plant metabolism and the production of valuable compounds. Research into PAL has implications for agriculture, where manipulating its activity could lead to improved crop resistance or enhanced production of beneficial phytochemicals. Furthermore, PAL has been explored for biotechnological applications, such as the biodegradation of phenylalanine or the production of cinnamic acid for industrial use. Its widespread distribution across different life forms highlights its fundamental importance in biochemistry.