Portal de Periódicos da CAPES

Plant Phenylacetaldehyde Synthase Is a Bifunctional Homotetrameric Enzyme That Catalyzes Phenylalanine Decarboxylation and Oxidation

2006; Elsevier BV; Volume: 281; Issue: 33 Linguagem: Inglês

10.1074/jbc.m602708200

1083-351X

Yasuhisa Kaminaga, Jennifer Schnepp, Greg Peel, Christine M. Kish, Gili Ben‐Nissan, David Weiss, Irina Orlova, Orly Lavie, David Rhodes, Karl V. Wood, D. Marshall Porterfield, Arthur J.L. Cooper, John V. Schloss, Eran Pichersky, Alexander Vainstein, Natalia Dudareva,

GABA and Rice Research

We have isolated and characterized Petunia hybrida cv. Mitchell phenylacetaldehyde synthase (PAAS), which catalyzes the formation of phenylacetaldehyde, a constituent of floral scent. PAAS is a cytosolic homotetrameric enzyme that belongs to group II pyridoxal 5'-phosphate-dependent amino-acid decarboxylases and shares extensive amino acid identity (approximately 65%) with plant L-tyrosine/3,4-dihydroxy-L-phenylalanine and L-tryptophan decarboxylases. It displays a strict specificity for phenylalanine with an apparent Km of 1.2 mM. PAAS is a bifunctional enzyme that catalyzes the unprecedented efficient coupling of phenylalanine decarboxylation to oxidation, generating phenylacetaldehyde, CO2, ammonia, and hydrogen peroxide in stoichiometric amounts.