title: Interactions between parallel pathways during biosynthesis of rosmarinic acid in cell suspension cultures of Coleus blumei.
abstract: Phenylalanine ammonia-lyase from an "over-producer" strain of Coleus blumei Benth. cell cultures accumulating high levels of rosmarinic acid (RA) has been shown to possess no special feed-back sensitivity to RA or its precursors. No tyrosine-3-hydroxylase activity could be detected in culture extracts and no specific inhibitors of tyrosine incorporation into RA were found. L-α-aminooxy-β-phenyl propionic acid, however, was effective in specifically blocking phenylalanine incorporation. This block also led to an accumulation of label from tyrosine in 4-hydroxyphenyllactic acid rather than in 3,4-dihydroxyphenylalanine (DOPA) or 3,4-dihydroxyphenyllactic acid. These observations require a re-evaluation of the possible role of DOPA as a major biogenic precursor to RA.
authors: Guelph-Waterloo Centre for Graduate Work in Chemistry, Department of Chemistry, University of Guelph, N1G 2W1, Guelph, Ont, Canada.
authors: B E
authors: BE
authors: Ellis
authors: S
authors: S
authors: Remmen
authors: G
authors: G
authors: Goeree