Elicitor-Induced l-Tyrosine Decarboxylase from Plant Cell Suspension Cultures

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Abstract
L-Tyrosine decarboxylase (EC 4.1.1.25) activity was induced in cell suspension cultures of Thalictrum rugosum Ait. and Escherichia californica Cham. with a yeast polysaccharide preparation (elicitor). The highest L-tyrosine decarboxylase activity in extracts from 7-day-old cell cultures of E. californica was observed 5 hours after addition of 30 to 40 micrograms elicitor per gram cell fresh weight. The enzyme extracted from cells of E. californica was purified 1540-fold to a specific activity of 2.6 micromoles CO2 produced per minute per milligram protein at pH 8.4 and 30.degree. C. Purified enzyme from T. rugosum showed a specific activity of 0.18 micromoles per minute per milligram protein. The purification procedure involved ammonium sulfate fractionation, anion-exchange fast protein liquid chromatography, ultrafiltration, and hydrophobic interaction chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the enzyme from the two plant cell cultures had subunits of identical molecular weight (56,300 .+-. 300 daltons).