Phenylalanine ammonia-lyase
Phenylalanine ammonia-lyase (PAL) is an enzyme that catalyzes the deamination of phenylalanine to trans-cinnamic acid and ammonia. This reaction is the first step in the phenylpropanoid pathway, which is responsible for the biosynthesis of a variety of secondary metabolites in plants, including flavonoids, lignin, and phenolic acids.
Structure[edit | edit source]
PAL is a tetramer with four identical subunits. Each subunit contains a MIO (3,5-dihydro-5-methylidene-4H-imidazol-4-one) group, which is essential for the enzyme's catalytic activity. The MIO group is formed by the spontaneous cyclization and dehydration of a tripeptide sequence in the protein chain.
Function[edit | edit source]
The primary function of PAL is to catalyze the non-oxidative deamination of phenylalanine to trans-cinnamic acid and ammonia. This reaction is the first step in the phenylpropanoid pathway, which leads to the production of a wide variety of secondary metabolites in plants. These metabolites play important roles in plant defense against pathogens and herbivores, as well as in plant-pollinator interactions.
Role in Disease[edit | edit source]
In humans, defects in the gene encoding PAL can lead to phenylketonuria, a metabolic disorder characterized by an inability to metabolize phenylalanine. This can result in the accumulation of phenylalanine and its metabolites in the body, leading to a variety of neurological symptoms.
See Also[edit | edit source]
Navigation: Wellness - Encyclopedia - Health topics - Disease Index - Drugs - World Directory - Gray's Anatomy - Keto diet - Recipes
Search WikiMD
Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro / Zepbound) available.
Advertise on WikiMD
WikiMD is not a substitute for professional medical advice. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates Wikipedia, licensed under CC BY SA or similar.Contributors: Prab R. Tumpati, MD