Elicitor-Induced l-Tyrosine Decarboxylase from Plant Cell Suspension Cultures 1: II. Partial Characterization

AUTOR(ES)

Marques, Ivano A.

RESUMO

Properties of purified l-tyrosine decarboxylase (EC 4.1.1.25) from elicitor-induced cell suspension cultures of Eschscholtzia californica Cham. and Thalictrum rugosum Ait. are described. l-Tyrosine decarboxylase is a dimeric enzyme with a molecular weight of 112,600 ± 600 daltons. The isoelectric point was estimated to be at pH 5.2 and pH 5.4 for the enzyme from E. californica and T. rugosum, respectively. The purified enzymes were stabilized in the presence of pyridoxal-5-phosphate. Optimum pH for the enzyme from both plants was found to be 8.4. Enzyme activity was dependent on exogeneously supplied pyridoxal-5-phosphate. The enzyme decarboxylated l-tyrosine and l-β-3,4-dihydroxyphenylalanine but was inactive toward l-phenylalanine and l-tryptophan. Apparent Km values of Eschscholtzia- and Thalictrum-decarboxylase for l-tyrosine were 0.25 ± 0.03 and 0.27 ± 0.04 millimolar, respectively. Similar affinities were found for l-3,4-dihydroxyphenylalanine. Eschscholtzial-tyrosine decarboxylase was strongly inhibited by the phenylalanine analogue l-α-aminooxy-β-phenylpropionate and largely unaffected by d,l-α-monofluoromethyl-3,4-dihydroxyphenylalanine and α-difluoromethyltyrosine.

Documentos Relacionados

• Elicitor-Induced l-Tyrosine Decarboxylase from Plant Cell Suspension Cultures 1: I. Induction and Purification
• Jasmonic acid is a signal transducer in elicitor-induced plant cell cultures.
• Conditioning of Parsley (Petroselinum crispum L.) Suspension Cells Increases Elicitor-Induced Incorporation of Cell Wall Phenolics.
• Vacuoles from Sugarcane Suspension Cultures 1: II. CHARACTERIZATION OF SUGAR UPTAKE
• Nitric Oxide Mediates the Fungal Elicitor-Induced Hypericin Production of Hypericum perforatum Cell Suspension Cultures through a Jasmonic-Acid-Dependent Signal Pathway1